1 =A(A × B) × 5 =A× (B × 5) A
Câu 3.
a × 3 =
3
× a
a : 1 =
a
(a × b) × 5 =
a
× (b × 5)
a : a =
1
(a khác 0)
a × 1 = 1 ×
a
=
a
0 : a =
0
(a khác 0)
2 × (m + n) = 2 × m + 2 ×
n
Câu 3.
a × 3 =
3
× a
a : 1 =
a
(a × b) × 5 =
a
× (b × 5)
a : a =
1
(a khác 0)
a × 1 = 1 ×
a
=
a
0 : a =
0
(a khác 0)
2 × (m + n) = 2 × m + 2 ×
n