Tính nhanh: 25 × 20 × 125 × 8 ‒ 8 × 20 × 5 × 125
Giải thích
25 × 20 × 125 × 8 ‒ 8 × 20 × 5 × 125
= 500 × 1000 − (8 × 125) × (20 × 5)
= 500 × 1000 − 1000 × 100
= 1000 × (500 − 100)
= 1000 × 400
= 400000.
25 × 20 × 125 × 8 ‒ 8 × 20 × 5 × 125
= 500 × 1000 − (8 × 125) × (20 × 5)
= 500 × 1000 − 1000 × 100
= 1000 × (500 − 100)
= 1000 × 400
= 400000.