3. Вычисли: 405 × 527; 522 × 417; 259 × 543.

405 × 527 = 405 × (500 + 20 + 7) = 202 500 + 8 100 + 2 835 = 213 435.

522 × 417 = 522 × (400 + 10 + 7) = 208 800 + 5 220 + 3 654 = 217 674.

259 × 543 = 259 × (500 + 40 + 3) = 129 500 + 10 360 + 777 = 140 637.