Tính: 143 × 25 + 25 × 35 + 75 × 39 + 75 × 139.
Giải thích
143 × 25 + 25 × 35 + 75 × 39 + 75 × 139
= [25 × (143 + 35)] + [75 × (39 + 139)]
= 25 × 178 + 75 × 178
= (25 + 75) × 178
= 100 × 178
= 17 800.
143 × 25 + 25 × 35 + 75 × 39 + 75 × 139
= [25 × (143 + 35)] + [75 × (39 + 139)]
= 25 × 178 + 75 × 178
= (25 + 75) × 178
= 100 × 178
= 17 800.