1)658 x 29 - 657 x 29 = 29 x (658 - 657) = 29
2) 64 x 258 - 64 x 39 - 64 x 19 = 64 x (258 - 39 - 19) = 64 x 200 = 12800
1)
658 x 29 - 657 x 29 = 29 x (658 - 657) = 29
2)
64 x 258 - 64 x 39 - 64 x 19 = 64 x (258 - 39 - 19) = 64 x 200 = 12800