Ответ:
309 × 734 = 309 × (700 + 30 + 4) = 216 300 + 9 270 + 1 236 = 226 806.
533 × 723 = 533 × (700 + 20 + 3) = 373 100 + 10 660 + 1 599 = 385 359.
575 × 389 = 575 × (300 + 80 + 9) = 172 500 + 46 000 + 5 175 = 223 675.
309 × 734 = 309 × (700 + 30 + 4) = 216 300 + 9 270 + 1 236 = 226 806.
533 × 723 = 533 × (700 + 20 + 3) = 373 100 + 10 660 + 1 599 = 385 359.
575 × 389 = 575 × (300 + 80 + 9) = 172 500 + 46 000 + 5 175 = 223 675.