10*3 23*10 10*2 21*30 4*5 15*16 8*9 27*16

1) 10 х 3 = 30;

2) 23 х 10 = 230;

3) 10 х 2 = 20;

4) 21 х 30 = 630, 20 х 30 = 600 и 1 х 30 = 30, 600 + 30 = 630;

5) 4 х 5 = 20;

6) 15 х 16 = 240, 15 х 10 = 150 и 15 х 2 х 3 = 90, 150 + 90 = 240;

7) 8 х 9 = 72;

8) 27 х 16 = 432, 20 х 16 = 320 и 7 х 6 = 42 и 7 х 10 = 70, 320 + 70 + 42 = 432.