diff --git a/src/copapy/__init__.py b/src/copapy/__init__.py
index e3fd7d7..3948a7e 100644
--- a/src/copapy/__init__.py
+++ b/src/copapy/__init__.py
@@ -2,7 +2,7 @@ from ._target import Target
 from ._basic_types import NumLike, variable, generic_sdb, iif
 from ._vectors import vector, distance, scalar_projection, angle_between, rotate_vector, vector_projection
 from ._matrices import matrix, identity, zeros, ones, diagonal
-from ._math import sqrt, abs, sin, cos, tan, asin, acos, atan, atan2, log, exp, pow, get_42, clamp, min, max
+from ._math import sqrt, abs, sign, sin, cos, tan, asin, acos, atan, atan2, log, exp, pow, get_42, clamp, min, max, relu
 
 __all__ = [
     "Target",
@@ -19,6 +19,7 @@ __all__ = [
     "sqrt",
     "abs",
     "sin",
+    "sign",
     "cos",
     "tan",
     "asin",
@@ -32,6 +33,7 @@ __all__ = [
     "clamp",
     "min",
     "max",
+    "relu",
     "distance",
     "scalar_projection",
     "angle_between",
diff --git a/src/copapy/_math.py b/src/copapy/_math.py
index 6e57f6a..6f775d5 100644
--- a/src/copapy/_math.py
+++ b/src/copapy/_math.py
@@ -278,6 +278,8 @@ def get_42(x: NumLike) -> variable[float] | float:
         return add_op('get_42', [x, x])
     return float((int(x) * 3.0 + 42.0) * 5.0 + 21.0)
 
+
+#TODO: Add vector support
 @overload
 def abs(x: U) -> U: ...
 @overload
@@ -292,7 +294,26 @@ def abs(x: U | variable[U]) -> Any:
         Absolute value of x
     """
     ret = (x < 0) * -x + (x >= 0) * x
-    return ret  # pyright: ignore[reportReturnType]
+    return ret  # REMpyright: ignore[reportReturnType]
+
+
+#TODO: Add vector support
+@overload
+def sign(x: U) -> U: ...
+@overload
+def sign(x: variable[U]) -> variable[U]: ...
+def sign(x: U | variable[U]) -> Any:
+    """Return 1 for positive numbers and -1 for negative numbers.
+    For an input of 0 the return value is 0.
+
+    Arguments:
+        x: Input value
+
+    Returns:
+        -1, 0 or 1
+    """
+    ret = (x > 0) - (x < 0)
+    return ret
 
 
 @overload
@@ -381,6 +402,17 @@ def lerp(v1: U | variable[U] | vector[U], v2: U | variable[U] | vector[U], t:  U
     return v1 * (1 - t) + v2 * t
 
 
+#TODO: Add vector support
+@overload
+def relu(x: U) -> U: ...
+@overload
+def relu(x: variable[U]) -> variable[U]: ...
+def relu(x: U | variable[U]) -> Any:
+    """Returns x for x > 0 and otherwise 0."""
+    ret = (x > 0) * x
+    return ret
+
+
 def _map2(self: VecNumLike, other: VecNumLike, func: Callable[[Any, Any], variable[U] | U]) -> vector[U]:
     """Applies a function to each element of the vector and a second vector or scalar."""
     if isinstance(self, vector) and isinstance(other, vector):