9 x 7 25 July 8, 2019 16 32 64 128 5 5 9 x 7 25 7 9 x 18 25 cancellation method 7 9 x 18 25 7 8 x 9 25 25 81 9 7 x 3 7 x 9 25 5 6 25 9 4 x 7 9 x 2 7 9 x 8 =
