diff --git a/Week04/functions_mehmet_ensar_dolgun.py b/Week04/functions_mehmet_ensar_dolgun.py
new file mode 100644
index 00000000..f232545e
--- /dev/null
+++ b/Week04/functions_mehmet_ensar_dolgun.py
@@ -0,0 +1,27 @@
+custom_power = lambda x=0, /, e=1: x**e
+
+def custom_equation(x: int = 0, y: int = 0, /, a: int = 1, b: int = 1, *, c: int = 1) -> float:
+    """
+    Calculates the mathematical equation.
+
+    :param x: The first base value.
+    :param y: The second base value.
+    :param a: The exponent for x.
+    :param b: The exponent for y.
+    :param c: The divisor.
+    :return: The result of the equation.
+    """
+
+    if c == 0:   # sıfıra bölme hatasını önlemek için
+        return 0.0
+
+    return (x ** a + y ** b) / c
+
+
+def fn_w_counter() -> tuple[int, dict[str, int]]:
+    if not hasattr(fn_w_counter, "counter"):
+        fn_w_counter.counter = 0
+
+    fn_w_counter.counter += 1
+
+    return fn_w_counter.counter, {fn_w_counter.__name__: fn_w_counter.counter}