Tính bằng hai cách. Mẫu: 4 x 2 x 2 Cách 1: 4 x 2 x 2 = (4 x 2) x 2

Cách 1: 3 x 2 x 2 = (3 x 2) x 2

                            = 6 x 2

                            = 12

Cách 2: 3 x 2 x 2 = 3 x (2 x 2)

                            = 3 x 4

                            = 12

Cách 1: 5 x 2 x 4 = (5 x 2) x 4

                            = 10 x 4

                            = 40

Cách 2: 5 x 2 x 4 = 5 x (2 x 4)

                            = 5 x 8

                            = 40