diff --git a/src/helper/numArray.test.ts b/src/helper/numArray.test.ts
index b5d1ae5..f70258e 100644
--- a/src/helper/numArray.test.ts
+++ b/src/helper/numArray.test.ts
@@ -67,21 +67,21 @@ describe('Number Array', () => {
     deepStrictEqual(actual, expected);
   });
 
-  it('should be able to substract values', () => {
+  it('should be able to subtract values', () => {
     const values1 = [10, 20, 30, 40, 50, 60, 70, 80, 90, 100];
     const values2 = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
     const expected = [9, 18, 27, 36, 45, 54, 63, 72, 81, 90];
 
-    const actual = NumArray.substract(values1, values2);
+    const actual = NumArray.subtract(values1, values2);
     deepStrictEqual(actual, expected);
   });
 
-  it('should be able to substract by', () => {
+  it('should be able to subtract by', () => {
     const values = [10, 20, 30, 40, 50, 60, 70, 80, 90, 100];
     const expected = [9, 19, 29, 39, 49, 59, 69, 79, 89, 99];
     const n = 1;
 
-    const actual = NumArray.substractBy(n, values);
+    const actual = NumArray.subtractBy(n, values);
     deepStrictEqual(actual, expected);
   });
 
diff --git a/src/helper/numArray.ts b/src/helper/numArray.ts
index 8a89dac..4c507ea 100644
--- a/src/helper/numArray.ts
+++ b/src/helper/numArray.ts
@@ -129,12 +129,12 @@ export function multiplyBy(n: number, values: number[]): number[] {
 }
 
 /**
- * Substracts values2 from values1.
+ * Subtracts values2 from values1.
  * @param values1 values one.
  * @param values2 values two.
  * @return result array.
  */
-export function substract(values1: number[], values2: number[]): number[] {
+export function subtract(values1: number[], values2: number[]): number[] {
   checkSameLength(values1, values2);
 
   const result = new Array<number>(values1.length);
@@ -147,12 +147,12 @@ export function substract(values1: number[], values2: number[]): number[] {
 }
 
 /**
- * Substractes n from values.
- * @param n substract value.
+ * Subtractes n from values.
+ * @param n subtract value.
  * @param values values array.
  * @return result array.
  */
-export function substractBy(n: number, values: number[]): number[] {
+export function subtractBy(n: number, values: number[]): number[] {
   const result = new Array<number>(values.length);
 
   for (let i = 0; i < values.length; i++) {
@@ -204,7 +204,7 @@ export function shiftRightBy(n: number, values: number[]): number[] {
  * @returns changes array.
  */
 export function changes(n: number, values: number[]): number[] {
-  return substract(values, shiftRightBy(n, values));
+  return subtract(values, shiftRightBy(n, values));
 }
 
 /**
diff --git a/src/indicator/momentum/awesomeOscillator.ts b/src/indicator/momentum/awesomeOscillator.ts
index 46f2eda..a55230d 100644
--- a/src/indicator/momentum/awesomeOscillator.ts
+++ b/src/indicator/momentum/awesomeOscillator.ts
@@ -1,7 +1,7 @@
 // Copyright (c) 2022 Onur Cinar. All Rights Reserved.
 // https://github.com/cinar/indicatorts
 
-import { add, divideBy, substract } from '../../helper/numArray';
+import { add, divideBy, subtract } from '../../helper/numArray';
 import { sma } from '../trend/sma';
 
 /**
@@ -18,6 +18,6 @@ export function awesomeOscillator(highs: number[], lows: number[]): number[] {
   const medianPrice = divideBy(2, add(lows, highs));
   const sma5 = sma(5, medianPrice);
   const sma34 = sma(34, medianPrice);
-  const ao = substract(sma5, sma34);
+  const ao = subtract(sma5, sma34);
   return ao;
 }
diff --git a/src/indicator/momentum/chaikinOscillator.ts b/src/indicator/momentum/chaikinOscillator.ts
index 27fd068..d60622a 100644
--- a/src/indicator/momentum/chaikinOscillator.ts
+++ b/src/indicator/momentum/chaikinOscillator.ts
@@ -1,7 +1,7 @@
 // Copyright (c) 2022 Onur Cinar. All Rights Reserved.
 // https://github.com/cinar/indicatorts
 
-import { substract } from '../../helper/numArray';
+import { subtract } from '../../helper/numArray';
 import { ema } from '../trend/ema';
 import { accumulationDistribution } from '../volume/accumulationDistribution';
 
@@ -39,7 +39,7 @@ export function chaikinOscillator(
   volumes: number[]
 ): ChaikinOscillator {
   const ad = accumulationDistribution(highs, lows, closings, volumes);
-  const co = substract(ema(fastPeriod, ad), ema(slowPeriod, ad));
+  const co = subtract(ema(fastPeriod, ad), ema(slowPeriod, ad));
 
   return {
     ad,
diff --git a/src/indicator/momentum/percentagePriceOscillator.ts b/src/indicator/momentum/percentagePriceOscillator.ts
index 1edb982..d97fff6 100644
--- a/src/indicator/momentum/percentagePriceOscillator.ts
+++ b/src/indicator/momentum/percentagePriceOscillator.ts
@@ -1,7 +1,7 @@
 // Copyright (c) 2022 Onur Cinar. All Rights Reserved.
 // https://github.com/cinar/indicatorts
 
-import { divide, multiplyBy, substract } from '../../helper/numArray';
+import { divide, multiplyBy, subtract } from '../../helper/numArray';
 import { ema } from '../trend/ema';
 
 /** Default fast period value. */
@@ -46,9 +46,9 @@ export function percentagePriceOscillator(
   const fastEma = ema(fastPeriod, prices);
   const slowEma = ema(slowPeriod, prices);
 
-  const ppo = multiplyBy(100, divide(substract(fastEma, slowEma), slowEma));
+  const ppo = multiplyBy(100, divide(subtract(fastEma, slowEma), slowEma));
   const signal = ema(signalPeriod, ppo);
-  const histogram = substract(ppo, signal);
+  const histogram = subtract(ppo, signal);
 
   return {
     ppo,
diff --git a/src/indicator/momentum/percentageVolumeOscillator.ts b/src/indicator/momentum/percentageVolumeOscillator.ts
index 8b79ab6..25beaee 100644
--- a/src/indicator/momentum/percentageVolumeOscillator.ts
+++ b/src/indicator/momentum/percentageVolumeOscillator.ts
@@ -1,7 +1,7 @@
 // Copyright (c) 2022 Onur Cinar. All Rights Reserved.
 // https://github.com/cinar/indicatorts
 
-import { divide, multiplyBy, substract } from '../../helper/numArray';
+import { divide, multiplyBy, subtract } from '../../helper/numArray';
 import { ema } from '../trend/ema';
 
 /** Default fast period value. */
@@ -46,9 +46,9 @@ export function percentageVolumeOscillator(
   const fastEma = ema(fastPeriod, volumes);
   const slowEma = ema(slowPeriod, volumes);
 
-  const pvo = multiplyBy(100, divide(substract(fastEma, slowEma), slowEma));
+  const pvo = multiplyBy(100, divide(subtract(fastEma, slowEma), slowEma));
   const signal = ema(signalPeriod, pvo);
-  const histogram = substract(pvo, signal);
+  const histogram = subtract(pvo, signal);
 
   return {
     pvo,
diff --git a/src/indicator/momentum/stochasticOscillator.ts b/src/indicator/momentum/stochasticOscillator.ts
index f9a40e9..c2b31d2 100644
--- a/src/indicator/momentum/stochasticOscillator.ts
+++ b/src/indicator/momentum/stochasticOscillator.ts
@@ -1,7 +1,7 @@
 // Copyright (c) 2022 Onur Cinar. All Rights Reserved.
 // https://github.com/cinar/indicatorts
 
-import { divide, multiplyBy, substract } from '../../helper/numArray';
+import { divide, multiplyBy, subtract } from '../../helper/numArray';
 import { mmin } from '../trend/mmin';
 import { mmax } from '../trend/mmax';
 import { sma } from '../trend/sma';
@@ -38,8 +38,8 @@ export function stochasticOscillator(
   const k = multiplyBy(
     100,
     divide(
-      substract(closings, lowestLow14),
-      substract(highestHigh14, lowestLow14)
+      subtract(closings, lowestLow14),
+      subtract(highestHigh14, lowestLow14)
     )
   );
 
diff --git a/src/indicator/momentum/williamsR.ts b/src/indicator/momentum/williamsR.ts
index e33ac97..53282c9 100644
--- a/src/indicator/momentum/williamsR.ts
+++ b/src/indicator/momentum/williamsR.ts
@@ -1,7 +1,7 @@
 // Copyright (c) 2022 Onur Cinar. All Rights Reserved.
 // https://github.com/cinar/indicatorts
 
-import { divide, multiplyBy, substract } from '../../helper/numArray';
+import { divide, multiplyBy, subtract } from '../../helper/numArray';
 import { mmax } from '../trend/mmax';
 import { mmin } from '../trend/mmin';
 
@@ -28,6 +28,6 @@ export function williamsR(
   const lowestLow = mmin(PERIOD, lows);
   return multiplyBy(
     -100,
-    divide(substract(highestHigh, closings), substract(highestHigh, lowestLow))
+    divide(subtract(highestHigh, closings), subtract(highestHigh, lowestLow))
   );
 }
diff --git a/src/indicator/trend/absolutePriceOscillator.ts b/src/indicator/trend/absolutePriceOscillator.ts
index e11550f..a157cde 100644
--- a/src/indicator/trend/absolutePriceOscillator.ts
+++ b/src/indicator/trend/absolutePriceOscillator.ts
@@ -1,7 +1,7 @@
 // Copyright (c) 2022 Onur Cinar. All Rights Reserved.
 // https://github.com/cinar/indicatorts
 
-import { substract } from '../../helper/numArray';
+import { subtract } from '../../helper/numArray';
 import { ema } from './ema';
 
 /**
@@ -26,7 +26,7 @@ export function absolutePriceOscillator(
 ): number[] {
   const fast = ema(fastPeriod, values);
   const slow = ema(slowPeriod, values);
-  const apo = substract(fast, slow);
+  const apo = subtract(fast, slow);
   return apo;
 }
 
diff --git a/src/indicator/trend/balanceOfPower.ts b/src/indicator/trend/balanceOfPower.ts
index 0478c96..a85b3d9 100644
--- a/src/indicator/trend/balanceOfPower.ts
+++ b/src/indicator/trend/balanceOfPower.ts
@@ -1,7 +1,7 @@
 // Copyright (c) 2022 Onur Cinar. All Rights Reserved.
 // https://github.com/cinar/indicatorts
 
-import { divide, substract } from '../../helper/numArray';
+import { divide, subtract } from '../../helper/numArray';
 
 /**
  * The Balance of Power (BOP) function calculates the strength of buying and
@@ -23,5 +23,5 @@ export function balanceOfPower(
   lows: number[],
   closings: number[]
 ): number[] {
-  return divide(substract(closings, openings), substract(highs, lows));
+  return divide(subtract(closings, openings), subtract(highs, lows));
 }
diff --git a/src/indicator/trend/chandeForecastOscillator.ts b/src/indicator/trend/chandeForecastOscillator.ts
index ce9cf72..11c8ded 100644
--- a/src/indicator/trend/chandeForecastOscillator.ts
+++ b/src/indicator/trend/chandeForecastOscillator.ts
@@ -5,7 +5,7 @@ import {
   divide,
   generateNumbers,
   multiplyBy,
-  substract,
+  subtract,
 } from '../../helper/numArray';
 import {
   linearRegressionUsingLeastSquare,
@@ -28,7 +28,7 @@ import {
 export function chandeForecastOscillator(closings: number[]): number[] {
   const x = generateNumbers(0, closings.length, 1);
   const r = linearRegressionUsingLeastSquare(x, closings);
-  const cfo = multiplyBy(100, divide(substract(closings, r), closings));
+  const cfo = multiplyBy(100, divide(subtract(closings, r), closings));
   return cfo;
 }
 
@@ -55,6 +55,6 @@ export function movingChandeForecastOscillator(
 ): number[] {
   const x = generateNumbers(0, closings.length, 1);
   const r = movingLinearRegressionUsingLeastSquare(period, x, closings);
-  const cfo = multiplyBy(100, divide(substract(closings, r), closings));
+  const cfo = multiplyBy(100, divide(subtract(closings, r), closings));
   return cfo;
 }
diff --git a/src/indicator/trend/communityChannelIndex.ts b/src/indicator/trend/communityChannelIndex.ts
index 6631e9a..5c0aa28 100644
--- a/src/indicator/trend/communityChannelIndex.ts
+++ b/src/indicator/trend/communityChannelIndex.ts
@@ -1,7 +1,7 @@
 // Copyright (c) 2022 Onur Cinar. All Rights Reserved.
 // https://github.com/cinar/indicatorts
 
-import { abs, divide, multiplyBy, substract } from '../../helper/numArray';
+import { abs, divide, multiplyBy, subtract } from '../../helper/numArray';
 import { sma } from './sma';
 import { typicalPrice } from './typicalPrice';
 
@@ -33,8 +33,8 @@ export function communityChannelIndex(
 ): number[] {
   const tp = typicalPrice(highs, lows, closings);
   const ma = sma(period, tp);
-  const md = sma(period, abs(substract(tp, ma)));
-  const cci = divide(substract(tp, ma), multiplyBy(0.015, md));
+  const md = sma(period, abs(subtract(tp, ma)));
+  const cci = divide(subtract(tp, ma), multiplyBy(0.015, md));
   return cci;
 }
 
diff --git a/src/indicator/trend/dema.ts b/src/indicator/trend/dema.ts
index 6467f01..1a84be6 100644
--- a/src/indicator/trend/dema.ts
+++ b/src/indicator/trend/dema.ts
@@ -1,7 +1,7 @@
 // Copyright (c) 2022 Onur Cinar. All Rights Reserved.
 // https://github.com/cinar/indicatorts
 
-import { multiplyBy, substract } from '../../helper/numArray';
+import { multiplyBy, subtract } from '../../helper/numArray';
 import { ema } from './ema';
 
 /**
@@ -17,7 +17,7 @@ export function dema(period: number, values: number[]): number[] {
   const ema1 = ema(period, values);
   const ema2 = ema(period, ema1);
 
-  const dema = substract(multiplyBy(2, ema1), ema2);
+  const dema = subtract(multiplyBy(2, ema1), ema2);
 
   return dema;
 }
diff --git a/src/indicator/trend/kdj.ts b/src/indicator/trend/kdj.ts
index 023e291..1d2dfea 100644
--- a/src/indicator/trend/kdj.ts
+++ b/src/indicator/trend/kdj.ts
@@ -1,7 +1,7 @@
 // Copyright (c) 2022 Onur Cinar. All Rights Reserved.
 // https://github.com/cinar/indicatorts
 
-import { divide, multiplyBy, substract } from '../../helper/numArray';
+import { divide, multiplyBy, subtract } from '../../helper/numArray';
 import { mmin } from './mmin';
 import { mmax } from './mmax';
 import { sma } from './sma';
@@ -52,12 +52,12 @@ export function kdj(
 
   const rsv = multiplyBy(
     100,
-    divide(substract(closings, lowest), substract(highest, lowest))
+    divide(subtract(closings, lowest), subtract(highest, lowest))
   );
 
   const k = sma(kPeriod, rsv);
   const d = sma(dPeriod, k);
-  const j = substract(multiplyBy(3, k), multiplyBy(2, d));
+  const j = subtract(multiplyBy(3, k), multiplyBy(2, d));
 
   return {
     k,
diff --git a/src/indicator/trend/macd.ts b/src/indicator/trend/macd.ts
index 649a53f..df369bd 100644
--- a/src/indicator/trend/macd.ts
+++ b/src/indicator/trend/macd.ts
@@ -1,7 +1,7 @@
 // Copyright (c) 2022 Onur Cinar. All Rights Reserved.
 // https://github.com/cinar/indicatorts
 
-import { substract } from '../../helper/numArray';
+import { subtract } from '../../helper/numArray';
 import { ema } from './ema';
 
 export interface MacdResult {
@@ -22,7 +22,7 @@ export function macd(closings: number[]): MacdResult {
   const ema12 = ema(12, closings);
   const ema26 = ema(26, closings);
 
-  const macdLine = substract(ema12, ema26);
+  const macdLine = subtract(ema12, ema26);
   const signalLine = ema(9, macdLine);
 
   return {
diff --git a/src/indicator/trend/massIndex.ts b/src/indicator/trend/massIndex.ts
index f79aa28..7f4d8b3 100644
--- a/src/indicator/trend/massIndex.ts
+++ b/src/indicator/trend/massIndex.ts
@@ -1,7 +1,7 @@
 // Copyright (c) 2022 Onur Cinar. All Rights Reserved.
 // https://github.com/cinar/indicatorts
 
-import { divide, substract } from '../../helper/numArray';
+import { divide, subtract } from '../../helper/numArray';
 import { ema } from './ema';
 import { msum } from './msum';
 
@@ -19,7 +19,7 @@ import { msum } from './msum';
  * @returns mi values.
  */
 export function massIndex(highs: number[], lows: number[]): number[] {
-  const ema1 = ema(9, substract(highs, lows));
+  const ema1 = ema(9, subtract(highs, lows));
   const ema2 = ema(9, ema1);
   const ratio = divide(ema1, ema2);
   const mi = msum(25, ratio);
diff --git a/src/indicator/trend/qstick.ts b/src/indicator/trend/qstick.ts
index 9844a6f..04d35da 100644
--- a/src/indicator/trend/qstick.ts
+++ b/src/indicator/trend/qstick.ts
@@ -1,7 +1,7 @@
 // Copyright (c) 2022 Onur Cinar. All Rights Reserved.
 // https://github.com/cinar/indicatorts
 
-import { substract } from '../../helper/numArray';
+import { subtract } from '../../helper/numArray';
 import { sma } from './sma';
 
 /**
@@ -19,5 +19,5 @@ export function qstick(
   openings: number[],
   closings: number[]
 ): number[] {
-  return sma(period, substract(closings, openings));
+  return sma(period, subtract(closings, openings));
 }
diff --git a/src/indicator/trend/tema.ts b/src/indicator/trend/tema.ts
index 10656b1..f7ca7ee 100644
--- a/src/indicator/trend/tema.ts
+++ b/src/indicator/trend/tema.ts
@@ -1,7 +1,7 @@
 // Copyright (c) 2022 Onur Cinar. All Rights Reserved.
 // https://github.com/cinar/indicatorts
 
-import { add, multiplyBy, substract } from '../../helper/numArray';
+import { add, multiplyBy, subtract } from '../../helper/numArray';
 import { ema } from './ema';
 
 /**
@@ -22,7 +22,7 @@ export function tema(period: number, values: number[]): number[] {
   const ema3 = ema(period, ema2);
 
   const temaLine = add(
-    substract(multiplyBy(3, ema1), multiplyBy(3, ema2)),
+    subtract(multiplyBy(3, ema1), multiplyBy(3, ema2)),
     ema3
   );
 
diff --git a/src/indicator/trend/trix.ts b/src/indicator/trend/trix.ts
index 5e1700a..e1dbc8b 100644
--- a/src/indicator/trend/trix.ts
+++ b/src/indicator/trend/trix.ts
@@ -1,7 +1,7 @@
 // Copyright (c) 2022 Onur Cinar. All Rights Reserved.
 // https://github.com/cinar/indicatorts
 
-import { divide, shiftRightAndFillBy, substract } from '../../helper/numArray';
+import { divide, shiftRightAndFillBy, subtract } from '../../helper/numArray';
 import { ema } from './ema';
 
 /**
@@ -24,6 +24,6 @@ export function trix(period: number, values: number[]): number[] {
   const ema2 = ema(period, ema1);
   const ema3 = ema(period, ema2);
   const previous = shiftRightAndFillBy(1, ema3[0], ema3);
-  const trix = divide(substract(ema3, previous), previous);
+  const trix = divide(subtract(ema3, previous), previous);
   return trix;
 }
diff --git a/src/indicator/trend/vortex.ts b/src/indicator/trend/vortex.ts
index e7074c8..3f66a51 100644
--- a/src/indicator/trend/vortex.ts
+++ b/src/indicator/trend/vortex.ts
@@ -7,7 +7,7 @@ import {
   divide,
   max,
   shiftRightBy,
-  substract,
+  subtract,
 } from '../../helper/numArray';
 import { msum } from './msum';
 
@@ -56,16 +56,16 @@ export function vortex(
 
   const prevClosings = shiftRightBy(1, closings);
 
-  const plusVm = abs(substract(highs, shiftRightBy(1, lows)));
-  const minusVm = abs(substract(lows, shiftRightBy(1, highs)));
+  const plusVm = abs(subtract(highs, shiftRightBy(1, lows)));
+  const minusVm = abs(subtract(lows, shiftRightBy(1, highs)));
 
   const plusVmSum = msum(VORTEX_PERIOD, plusVm);
   const minusVmSum = msum(VORTEX_PERIOD, minusVm);
 
   const tr = max(
-    substract(highs, lows),
-    abs(substract(highs, prevClosings)),
-    abs(substract(lows, prevClosings))
+    subtract(highs, lows),
+    abs(subtract(highs, prevClosings)),
+    abs(subtract(lows, prevClosings))
   );
 
   const trSum = msum(VORTEX_PERIOD, tr);
diff --git a/src/indicator/volatility/accelerationBands.ts b/src/indicator/volatility/accelerationBands.ts
index fb7eff9..348dde4 100644
--- a/src/indicator/volatility/accelerationBands.ts
+++ b/src/indicator/volatility/accelerationBands.ts
@@ -8,7 +8,7 @@ import {
   divide,
   multiply,
   multiplyBy,
-  substract,
+  subtract,
 } from '../../helper/numArray';
 import { sma } from '../trend/sma';
 
@@ -41,7 +41,7 @@ export function accelerationBands(
 ): AccelerationBands {
   checkSameLength(highs, lows, closings);
 
-  const k = divide(substract(highs, lows), add(highs, lows));
+  const k = divide(subtract(highs, lows), add(highs, lows));
 
   const upperBand = sma(20, multiply(highs, addBy(1, multiplyBy(4, k))));
   const middleBand = sma(20, closings);
diff --git a/src/indicator/volatility/atr.ts b/src/indicator/volatility/atr.ts
index 64200d8..4b54594 100644
--- a/src/indicator/volatility/atr.ts
+++ b/src/indicator/volatility/atr.ts
@@ -1,7 +1,7 @@
 // Copyright (c) 2022 Onur Cinar. All Rights Reserved.
 // https://github.com/cinar/indicatorts
 
-import { checkSameLength, max, substract } from '../../helper/numArray';
+import { checkSameLength, max, subtract } from '../../helper/numArray';
 import { sma } from '../../indicator/trend/sma';
 
 /**
@@ -35,9 +35,9 @@ export function atr(
   checkSameLength(highs, lows, closings);
 
   const trLine = max(
-    substract(highs, lows),
-    substract(highs, closings),
-    substract(closings, lows)
+    subtract(highs, lows),
+    subtract(highs, closings),
+    subtract(closings, lows)
   );
 
   const atrLine = sma(period, trLine);
diff --git a/src/indicator/volatility/bollingerBands.ts b/src/indicator/volatility/bollingerBands.ts
index 313c546..eece22a 100644
--- a/src/indicator/volatility/bollingerBands.ts
+++ b/src/indicator/volatility/bollingerBands.ts
@@ -1,7 +1,7 @@
 // Copyright (c) 2022 Onur Cinar. All Rights Reserved.
 // https://github.com/cinar/indicatorts
 
-import { add, multiplyBy, substract } from '../../helper/numArray';
+import { add, multiplyBy, subtract } from '../../helper/numArray';
 import { sma } from '../trend/sma';
 import { mstd } from './mstd';
 
@@ -30,7 +30,7 @@ export function bollingerBands(closings: number[]): BollingerBands {
   const std2 = multiplyBy(2, mstd(BB_PERIOD, closings));
   const middleBand = sma(BB_PERIOD, closings);
   const upperBand = add(middleBand, std2);
-  const lowerBand = substract(middleBand, std2);
+  const lowerBand = subtract(middleBand, std2);
 
   return {
     upperBand,
diff --git a/src/indicator/volatility/bollingerBandsWidth.ts b/src/indicator/volatility/bollingerBandsWidth.ts
index 95f051f..ea149fd 100644
--- a/src/indicator/volatility/bollingerBandsWidth.ts
+++ b/src/indicator/volatility/bollingerBandsWidth.ts
@@ -1,7 +1,7 @@
 // Copyright (c) 2022 Onur Cinar. All Rights Reserved.
 // https://github.com/cinar/indicatorts
 
-import { divide, substract } from '../../helper/numArray';
+import { divide, subtract } from '../../helper/numArray';
 import { ema } from '../trend/ema';
 import { BollingerBands } from './bollingerBands';
 
@@ -30,7 +30,7 @@ export interface BollingerBandsWidth {
  */
 export function bollingerBandsWidth(bb: BollingerBands): BollingerBandsWidth {
   const bandWidth = divide(
-    substract(bb.upperBand, bb.lowerBand),
+    subtract(bb.upperBand, bb.lowerBand),
     bb.middleBand
   );
 
diff --git a/src/indicator/volatility/chandelierExit.ts b/src/indicator/volatility/chandelierExit.ts
index 3ef2373..acb8c12 100644
--- a/src/indicator/volatility/chandelierExit.ts
+++ b/src/indicator/volatility/chandelierExit.ts
@@ -1,7 +1,7 @@
 // Copyright (c) 2022 Onur Cinar. All Rights Reserved.
 // https://github.com/cinar/indicatorts
 
-import { add, multiplyBy, substract } from '../../helper/numArray';
+import { add, multiplyBy, subtract } from '../../helper/numArray';
 import { mmax } from '../trend/mmax';
 import { mmin } from '../trend/mmin';
 import { atr } from './atr';
@@ -38,7 +38,7 @@ export function chandelierExit(
   const highestHigh = mmax(PERIOD, highs);
   const lowestLow = mmin(PERIOD, lows);
 
-  const exitLong = substract(highestHigh, atrLine3);
+  const exitLong = subtract(highestHigh, atrLine3);
   const exitShort = add(lowestLow, atrLine3);
 
   return {
diff --git a/src/indicator/volatility/keltnerChannel.ts b/src/indicator/volatility/keltnerChannel.ts
index c315eca..a0eb13f 100644
--- a/src/indicator/volatility/keltnerChannel.ts
+++ b/src/indicator/volatility/keltnerChannel.ts
@@ -1,7 +1,7 @@
 // Copyright (c) 2022 Onur Cinar. All Rights Reserved.
 // https://github.com/cinar/indicatorts
 
-import { add, multiplyBy, substract } from '../../helper/numArray';
+import { add, multiplyBy, subtract } from '../../helper/numArray';
 import { ema } from '../trend/ema';
 import { atr } from './atr';
 
@@ -45,7 +45,7 @@ export function keltnerChannel(
 
   const middleLine = ema(period, closings);
   const upperBand = add(middleLine, atr2);
-  const lowerBand = substract(middleLine, atr2);
+  const lowerBand = subtract(middleLine, atr2);
 
   return {
     middleLine,
diff --git a/src/indicator/volatility/projectionOscillator.ts b/src/indicator/volatility/projectionOscillator.ts
index c6989c9..183e1fa 100644
--- a/src/indicator/volatility/projectionOscillator.ts
+++ b/src/indicator/volatility/projectionOscillator.ts
@@ -7,7 +7,7 @@ import {
   generateNumbers,
   multiply,
   multiplyBy,
-  substract,
+  subtract,
 } from '../../helper/numArray';
 import { movingLeastSquare } from '../../helper/regression';
 import { ema } from '../trend/ema';
@@ -59,8 +59,8 @@ export function projectionOscillator(
   const pl = mmin(period, vLows);
 
   const po = divide(
-    multiplyBy(100, substract(closings, pl)),
-    substract(pu, pl)
+    multiplyBy(100, subtract(closings, pl)),
+    subtract(pu, pl)
   );
   const spo = ema(smooth, po);
 
diff --git a/src/indicator/volatility/ulcerIndex.ts b/src/indicator/volatility/ulcerIndex.ts
index 6e3b0d0..93a29ff 100644
--- a/src/indicator/volatility/ulcerIndex.ts
+++ b/src/indicator/volatility/ulcerIndex.ts
@@ -6,7 +6,7 @@ import {
   multiply,
   multiplyBy,
   sqrt,
-  substract,
+  subtract,
 } from '../../helper/numArray';
 import { mmax } from '../trend/mmax';
 import { sma } from '../trend/sma';
@@ -34,7 +34,7 @@ export function ulcerIndex(period: number, closings: number[]): number[] {
   const highClosings = mmax(period, closings);
   const percentageDrawdown = multiplyBy(
     100,
-    divide(substract(closings, highClosings), highClosings)
+    divide(subtract(closings, highClosings), highClosings)
   );
   const squaredAverage = sma(
     period,
diff --git a/src/indicator/volume/accumulationDistribution.ts b/src/indicator/volume/accumulationDistribution.ts
index 9509129..49f8205 100644
--- a/src/indicator/volume/accumulationDistribution.ts
+++ b/src/indicator/volume/accumulationDistribution.ts
@@ -1,7 +1,7 @@
 // Copyright (c) 2022 Onur Cinar. All Rights Reserved.
 // https://github.com/cinar/indicatorts
 
-import { divide, multiply, substract } from '../../helper/numArray';
+import { divide, multiply, subtract } from '../../helper/numArray';
 
 /**
  * Accumulation/Distribution Indicator (A/D). Cumulative indicator
@@ -25,8 +25,8 @@ export function accumulationDistribution(
   volume: number[]
 ): number[] {
   const mfm = divide(
-    substract(substract(closings, lows), substract(highs, closings)),
-    substract(highs, lows)
+    subtract(subtract(closings, lows), subtract(highs, closings)),
+    subtract(highs, lows)
   );
 
   const mfv = multiply(mfm, volume);
diff --git a/src/indicator/volume/chaikinMoneyFlow.ts b/src/indicator/volume/chaikinMoneyFlow.ts
index a77cdfe..1155dae 100644
--- a/src/indicator/volume/chaikinMoneyFlow.ts
+++ b/src/indicator/volume/chaikinMoneyFlow.ts
@@ -1,7 +1,7 @@
 // Copyright (c) 2022 Onur Cinar. All Rights Reserved.
 // https://github.com/cinar/indicatorts
 
-import { divide, multiply, substract } from '../../helper/numArray';
+import { divide, multiply, subtract } from '../../helper/numArray';
 import { msum } from '../trend/msum';
 
 /**
@@ -30,8 +30,8 @@ export function chaikinMoneyFlow(
   volumes: number[]
 ): number[] {
   const moneyFlowMultipler = divide(
-    substract(substract(closings, lows), substract(highs, closings)),
-    substract(highs, lows)
+    subtract(subtract(closings, lows), subtract(highs, closings)),
+    subtract(highs, lows)
   );
 
   const moneyFlowVolume = multiply(moneyFlowMultipler, volumes);
diff --git a/src/indicator/volume/easeOfMovement.ts b/src/indicator/volume/easeOfMovement.ts
index 078f065..254c342 100644
--- a/src/indicator/volume/easeOfMovement.ts
+++ b/src/indicator/volume/easeOfMovement.ts
@@ -6,7 +6,7 @@ import {
   changes,
   divide,
   divideBy,
-  substract,
+  subtract,
 } from '../../helper/numArray';
 import { sma } from '../trend/sma';
 
@@ -37,7 +37,7 @@ export function easeOfMovement(
   volumes: number[]
 ): number[] {
   const distanceMoved = changes(1, divideBy(2, add(highs, lows)));
-  const boxRatio = divide(divideBy(100000000, volumes), substract(highs, lows));
+  const boxRatio = divide(divideBy(100000000, volumes), subtract(highs, lows));
   const emv = sma(period, divide(distanceMoved, boxRatio));
   return emv;
 }
diff --git a/src/indicator/volume/volumePriceTrend.ts b/src/indicator/volume/volumePriceTrend.ts
index fadc287..3ebe4b0 100644
--- a/src/indicator/volume/volumePriceTrend.ts
+++ b/src/indicator/volume/volumePriceTrend.ts
@@ -5,7 +5,7 @@ import {
   divide,
   multiply,
   shiftRightAndFillBy,
-  substract,
+  subtract,
 } from '../../helper/numArray';
 import { msum } from '../trend/msum';
 
@@ -26,7 +26,7 @@ export function volumePriceTrend(
   const previousClosings = shiftRightAndFillBy(1, closings[0], closings);
   const vpt = multiply(
     volumes,
-    divide(substract(closings, previousClosings), previousClosings)
+    divide(subtract(closings, previousClosings), previousClosings)
   );
   return msum(vpt.length, vpt);
 }
diff --git a/src/strategy/volume/volumeWeightedAveragePriceStrategy.ts b/src/strategy/volume/volumeWeightedAveragePriceStrategy.ts
index 21414fb..316bfd0 100644
--- a/src/strategy/volume/volumeWeightedAveragePriceStrategy.ts
+++ b/src/strategy/volume/volumeWeightedAveragePriceStrategy.ts
@@ -1,7 +1,7 @@
 // Copyright (c) 2022 Onur Cinar. All Rights Reserved.
 // https://github.com/cinar/indicatorts
 
-import { substract } from '../../helper/numArray';
+import { subtract } from '../../helper/numArray';
 import { defaultVolumeWeightedAveragePrice } from '../../indicator/volume/volumeWeightedAveragePrice';
 import { Action } from '../action';
 import { Asset } from '../asset';
@@ -18,7 +18,7 @@ import { Asset } from '../asset';
 export function volumeWeightedAveragePriceStrategy(asset: Asset): Action[] {
   const vwap = defaultVolumeWeightedAveragePrice(asset.closings, asset.volumes);
 
-  const diff = substract(vwap, asset.closings);
+  const diff = subtract(vwap, asset.closings);
 
   return diff.map((value) => {
     if (value > 0) {