21 - 3 x 7 =
24 - 3 x 8 =
27 - 3 x 9 =
30 - 3 x 10 =
0 - 4 x 0 =
28 - 4 x 7 =
32 - 4 x 8 =
36 - 4 x 9 =
40 - 4 x 10 =