Bài 1 (trang 32 SGK Toán lớp 3)
Tính nhẩm:
a) 7 × 1 = 7 × 8 7 × 6 = 7 × 5 =
7 × 2 = 7 × 9 = 7 × 4 = 0 × 7 =
7 × 3 = 7 × 7 = 7 × 0 = 7 × 10 =
b) 7 × 2 = 4 × 7 = 7 × 6 = 3 ×7 = 5 × 7 =
2 × 7 = 7 × 4 = 6 ×7 = 7 × 3 = 7 × 5 =
Lời giải
a) 7 × 1 = 7 7 × 8 = 56 7 × 6 = 42 7 × 5 = 35
7 × 2 = 14 7 × 9 = 63 7 × 4 = 28 0 × 7 = 0
7 × 3 = 21 7 × 7 = 49 7 × 0 = 0 7 × 10 = 70
b) 7 × 2 = 14 4 × 7 = 28 7 × 6 = 42 3 × 7 = 21 5 × 7 = 35
2 × 7 = 14 7 × 4 = 28 6 ×7 = 42 7 × 3 = 21 7 × 5 = 35.
Tham khảo toàn bộ: Toán lớp 3