diff --git a/lesson-7/task1.py b/lesson-7/task1.py
new file mode 100644
index 0000000..aa0e064
--- /dev/null
+++ b/lesson-7/task1.py
@@ -0,0 +1,53 @@
+import random
+
+
+class MatrixException(Exception):
+    pass
+
+
+class Matrix:
+    def __init__(self, matrix):
+        self.matrix = matrix
+        self.rows = len(matrix)
+        self.cols = len(matrix[0])
+
+    def __str__(self):
+        return "\n".join([' '.join(map(str, tmp)) for tmp in self.matrix])
+
+    def __add__(self, other):
+        if self.rows != other.rows or self.cols != other.cols:
+            raise MatrixException('Matrices has different size')
+        # res = [map(sum, zip(*tmp)) for tmp in zip(self.matrix, other.matrix)]
+        res = generate_matrix(self.rows, self.cols, nulls=True)
+        for i in range(self.rows):
+            for j in range(self.cols):
+                res[i][j] = self.matrix[i][j] + other.matrix[i][j]
+        return Matrix(res)
+
+
+def generate_matrix(rows: int, cols: int, *, nulls: bool = False) -> list:
+    matrix = []
+    for i in range(rows):
+        matrix.append([random.randint(0, 100) if not nulls else 0 for j in range(cols)])
+    return matrix
+
+
+matrix1 = Matrix(generate_matrix(
+    int(input('Enter rows matrix 1: ')),
+    int(input('Enter cols matrix 1: ')),
+))
+
+matrix2 = Matrix(generate_matrix(
+    int(input('Enter rows matrix 2: ')),
+    int(input('Enter cols matrix 2: ')),
+))
+
+print('Matrix 1')
+print(matrix1)
+print('Matrix 2')
+print(matrix2)
+try:
+    print('Matrix sum:')
+    print(matrix1 + matrix2)
+except MatrixException as e:
+    print(e)
diff --git a/lesson-7/task2.py b/lesson-7/task2.py
new file mode 100644
index 0000000..700b1e5
--- /dev/null
+++ b/lesson-7/task2.py
@@ -0,0 +1,29 @@
+from abc import ABC, abstractmethod
+
+
+class Cloth(ABC):
+    @abstractmethod
+    def calc(self):
+        pass
+
+
+class Coat(Cloth):
+    def __init__(self, v):
+        self.__v = v
+
+    @property
+    def calc(self):
+        return self.__v / 6.5 + 0.5
+
+
+class Suit(Cloth):
+    def __init__(self, h):
+        self.__h = h
+
+    @property
+    def calc(self):
+        return self.__h * 2 + 0.3
+
+
+print(Coat(10).calc)
+print(Suit(8).calc)
diff --git a/lesson-7/task3.py b/lesson-7/task3.py
new file mode 100644
index 0000000..bdfe41e
--- /dev/null
+++ b/lesson-7/task3.py
@@ -0,0 +1,47 @@
+class CellSubException(Exception):
+    pass
+
+
+class CellTruedivException(Exception):
+    pass
+
+
+class Cell:
+    def __init__(self, count: int):
+        self.count = count
+
+    def __add__(self, other):
+        return Cell(self.count + other.count)
+
+    def __sub__(self, other):
+        if self.count < other.count:
+            raise CellSubException('sub error')
+        return Cell(self.count - other.count)
+
+    def __mul__(self, other):
+        return self.count * other.count
+
+    def __truediv__(self, other):
+        if other.count == 0:
+            raise CellTruedivException('division by zero')
+        if self.count // other.count == 0:
+            raise CellTruedivException('zero result')
+        return Cell(self.count // other.count)
+
+    def make_order(self, in_row: int):
+        for i in range(self.count):
+            print('*', end='')
+            if (i+1) % in_row == 0:
+                print('')
+        print('')
+
+
+c1 = Cell(20)
+c2 = Cell(8)
+
+print('SUM:', c1 + c2)
+print('SUB:', c1 - c2)
+print('MUL:', c1 * c2)
+print('TRUEDIV:', c1 / c2)
+
+c1.make_order(4)