diff --git a/deno.json b/deno.json
index 9f8c718..c2cc0aa 100644
--- a/deno.json
+++ b/deno.json
@@ -5,6 +5,7 @@
     "input": "deno run -NEWR src/crypto.ts --get=$DAY",
     "solve": "deno run -R src/$DAY/main.ts",
     "test": "deno test -R src/**/test.ts",
+    "test:all": "deno test -R src/**/*test.ts",
     "test:input": "deno test -R src/**/input.test.ts"
   },
   "imports": {
diff --git a/src/07/main.ts b/src/07/main.ts
index 3460278..fed7a62 100644
--- a/src/07/main.ts
+++ b/src/07/main.ts
@@ -1,8 +1,8 @@
 // { calibrationSum: 4998764814652, concatCalibrationSum: 37598910447546 }
-// Elapsed: 207ms
+// Elapsed: 94ms
 
 function concatNumbers(a: number, b: number) {
-  return Number(`${a}${b}`);
+  return a * Math.pow(10, Math.ceil(Math.log10(b + 1))) + b;
 }
 
 function numbersProduceTestValue(