13 x 9 = 117
1 x 45, 3 x 15, 5 x 9, 9 x 5, 15 x 3, 45 x 1.
90 Do 9*5*2 If div by 9, its div by 3 If div by 2 and 3 its div by 6 its div by 2,5 and 9 because we mutiplied those
3*39 = 117 9*13 = 117
9(9) = 81 base 10. In base 4 it is 1101 (64 + 16 + 1), etc.
Multiply by ten and then subtract the number being mutiplied - 22 x 9 = 220 - 22 = 198
5/9
5/9 * 9/16 * 7/5 = 7/16
1/9 / 9/5 =5/18 beacuase (1/9)*5/9=5/18
2/9 + 5/9 = 7/9
(4/9) * (5/9) = 20/81
5/9 − 5/12 = 5/36