34*99=,99*23=,65*45

Найдем значение выражений:

1) 34 * 99 = (30 + 4) * 99 = 99 * 30 + 99 * 4 = 90 * 30 + 9 * 30 + 90 * 4 + 9 * 4 = 2700 + 270 + 360 + 36 = 2700 + 630 + 36 = 2700 + 666 = 3366;

2) 99 * 23 = 90 * 23 + 9 * 23 = 90 * 20 + 90 * 3 + 9 * 20 + 9 * 3 = 1800 + 270 + 180 + 27 = 1800 + 450 + 27 = 2250 + 27 = 2277;

3) 65 * 45 = 60 * 45 + 5 * 45 = 60 * 40 + 60 * 5 + 5 * 40 + 5 * 5 = 2400 + 300 + 200 + 25 = 2400 + 500 + 25 = 2900 + 25 = 2925.