diff --git a/practica/math/statistic/Number_square.py b/practica/math/statistic/Number_square.py
new file mode 100644
index 0000000..736f058
--- /dev/null
+++ b/practica/math/statistic/Number_square.py
@@ -0,0 +1,3 @@
+# возвращаем квадрат из числа
+def get_sqrt(x):
+    return x ** 0.5
\ No newline at end of file
diff --git a/practica/math/statistic/Standard deviation.py b/practica/math/statistic/Standard deviation.py
new file mode 100644
index 0000000..8a22e16
--- /dev/null
+++ b/practica/math/statistic/Standard deviation.py	
@@ -0,0 +1,14 @@
+# Среднеквадратичное отклонение sd
+list_data = [int(value) for value in input().split()]
+n = len(list_data)
+Sum = 0
+for value in list_data:
+    Sum += value
+    SUm=Sum/n
+Sum = 0
+for value in list_data:
+    a = (value - SUm)**2
+    Sum += a
+    D = (Sum / (n - 1 ))
+    sd = D ** 0.5
+    print (sd)
diff --git a/practica/math/statistic/average value.py b/practica/math/statistic/average value.py
new file mode 100644
index 0000000..397e553
--- /dev/null
+++ b/practica/math/statistic/average value.py	
@@ -0,0 +1,3 @@
+   # среднее значение
+def find_average(x):
+    return sum(x) / len(x)
\ No newline at end of file
diff --git a/practica/math/statistic/median.py b/practica/math/statistic/median.py
new file mode 100644
index 0000000..46c3602
--- /dev/null
+++ b/practica/math/statistic/median.py
@@ -0,0 +1,6 @@
+# медиана
+def find_median(x):
+    if len(x) % 2 == 0:
+        return (x[len(x) // 2] + x[len(x) // 2 -1]) / 2
+    else:
+        return x[len(x) // 2]
\ No newline at end of file
diff --git a/practica/math/statistic/renge.py b/practica/math/statistic/renge.py
new file mode 100644
index 0000000..8f8192e
--- /dev/null
+++ b/practica/math/statistic/renge.py
@@ -0,0 +1,4 @@
+# размах
+def find_range(x):
+    x_copy = sorted(x)
+    return abs(x_copy[-1] - x_copy[0])
\ No newline at end of file