If you notice there is a pattern like for instance 2 = 6 you have to multiply 2*3 to get six and for 3 to get 12 you multiply 3 * 4 and so on. but once it gets to six it skips over a couple of numbers well that is to make you confused and make you do the rest. So to finish it you find the missing numbers 7*8 = 56(7 = 56), 8* 9 = 72(8 = 72), and finally 9 * 10 = 90, or 9 = 90.
