See if you can fill in the missing numbers:
54 x 6 = 50 x 6 + (4) x 6 18 x 4 = (10) x 4 + 8 x 4 (42) x 7 = 40 x 7 + 2 x 7 32 x 5 = (30) x 5 + 2 x 5