diff --git a/benchmarks/benchmarks.py b/benchmarks/benchmarks.py
index f671a66..95f53d1 100644
--- a/benchmarks/benchmarks.py
+++ b/benchmarks/benchmarks.py
@@ -12,7 +12,7 @@
 from tdastro.astro_utils.snia_utils import DistModFromRedshift, HostmassX1Func, X0FromDistMod
 from tdastro.astro_utils.unit_utils import fnu_to_flam
 from tdastro.base_models import FunctionNode
-from tdastro.rand_nodes.np_random import NumpyRandomFunc
+from tdastro.math_nodes.np_random import NumpyRandomFunc
 from tdastro.sources.sncomso_models import SncosmoWrapperModel
 
 
diff --git a/src/tdastro/base_models.py b/src/tdastro/base_models.py
index d8024c5..24e51b9 100644
--- a/src/tdastro/base_models.py
+++ b/src/tdastro/base_models.py
@@ -623,28 +623,6 @@ def build_pytree(self, graph_state, partial=None):
         return partial
 
 
-class SingleVariableNode(ParameterizedNode):
-    """A ParameterizedNode holding a single pre-defined variable.
-
-    Notes
-    -----
-    Often used for testing, but can be used to make graph dependencies clearer.
-
-    Parameters
-    ----------
-    name : `str`
-        The parameter name.
-    value : any
-        The parameter value.
-    **kwargs : `dict`, optional
-        Any additional keyword arguments.
-    """
-
-    def __init__(self, name, value, **kwargs):
-        super().__init__(**kwargs)
-        self.add_parameter(name, value, **kwargs)
-
-
 class FunctionNode(ParameterizedNode):
     """A class to wrap functions and their argument settings.
 
diff --git a/src/tdastro/math_nodes/single_value_node.py b/src/tdastro/math_nodes/single_value_node.py
new file mode 100644
index 0000000..2e6881d
--- /dev/null
+++ b/src/tdastro/math_nodes/single_value_node.py
@@ -0,0 +1,25 @@
+"""A simple node used for testing."""
+
+from tdastro.base_models import ParameterizedNode
+
+
+class SingleVariableNode(ParameterizedNode):
+    """A ParameterizedNode holding a single pre-defined variable.
+
+    Notes
+    -----
+    Often used for testing, but can be used to make graph dependencies clearer.
+
+    Parameters
+    ----------
+    name : `str`
+        The parameter name.
+    value : any
+        The parameter value.
+    **kwargs : `dict`, optional
+        Any additional keyword arguments.
+    """
+
+    def __init__(self, name, value, **kwargs):
+        super().__init__(**kwargs)
+        self.add_parameter(name, value, **kwargs)
diff --git a/tests/tdastro/astro_utils/test_snia_utils.py b/tests/tdastro/astro_utils/test_snia_utils.py
index f4ae7f6..8156d2e 100644
--- a/tests/tdastro/astro_utils/test_snia_utils.py
+++ b/tests/tdastro/astro_utils/test_snia_utils.py
@@ -1,8 +1,8 @@
 import numpy as np
 import pytest
 from scipy.stats import norm
-from tdastro.math_nodess.snia_utils import DistModFromRedshift, HostmassX1Distr, HostmassX1Func
-from tdastro.rand_nodes.np_random import NumpyRandomFunc
+from tdastro.astro_utils.snia_utils import DistModFromRedshift, HostmassX1Distr, HostmassX1Func
+from tdastro.math_nodes.np_random import NumpyRandomFunc
 
 
 def test_hostmass_x1_distr():
diff --git a/tests/tdastro/rand_nodes/test_given_sampler.py b/tests/tdastro/math_nodes/test_given_sampler.py
similarity index 100%
rename from tests/tdastro/rand_nodes/test_given_sampler.py
rename to tests/tdastro/math_nodes/test_given_sampler.py
diff --git a/tests/tdastro/rand_nodes/test_np_random.py b/tests/tdastro/math_nodes/test_np_random.py
similarity index 100%
rename from tests/tdastro/rand_nodes/test_np_random.py
rename to tests/tdastro/math_nodes/test_np_random.py
diff --git a/tests/tdastro/rand_nodes/test_scipy_random.py b/tests/tdastro/math_nodes/test_scipy_random.py
similarity index 100%
rename from tests/tdastro/rand_nodes/test_scipy_random.py
rename to tests/tdastro/math_nodes/test_scipy_random.py
diff --git a/tests/tdastro/math_nodes/test_single_value_node.py b/tests/tdastro/math_nodes/test_single_value_node.py
new file mode 100644
index 0000000..7548d9f
--- /dev/null
+++ b/tests/tdastro/math_nodes/test_single_value_node.py
@@ -0,0 +1,10 @@
+from tdastro.math_nodes.single_value_node import SingleVariableNode
+
+
+def test_single_variable_node():
+    """Test that we can create and query a SingleVariableNode."""
+    node = SingleVariableNode("A", 10.0)
+    assert str(node) == "SingleVariableNode"
+
+    state = node.sample_parameters()
+    assert node.get_param(state, "A") == 10
diff --git a/tests/tdastro/test_base_models.py b/tests/tdastro/test_base_models.py
index 76f88ab..cbb25c5 100644
--- a/tests/tdastro/test_base_models.py
+++ b/tests/tdastro/test_base_models.py
@@ -3,7 +3,8 @@
 import jax
 import numpy as np
 import pytest
-from tdastro.base_models import FunctionNode, ParameterizedNode, ParameterSource, SingleVariableNode
+from tdastro.base_models import FunctionNode, ParameterizedNode, ParameterSource
+from tdastro.math_nodes.single_value_node import SingleVariableNode
 
 
 def _sampler_fun(**kwargs):
@@ -215,15 +216,6 @@ def test_parameterized_node_build_pytree():
     assert pytree["B"]["value2"] == 3.0
 
 
-def test_single_variable_node():
-    """Test that we can create and query a SingleVariableNode."""
-    node = SingleVariableNode("A", 10.0)
-    assert str(node) == "SingleVariableNode"
-
-    state = node.sample_parameters()
-    assert node.get_param(state, "A") == 10
-
-
 def test_function_node_basic():
     """Test that we can create and query a FunctionNode."""
     my_func = FunctionNode(_test_func, value1=1.0, value2=2.0)