anything x0 = 0
anything x1 = that number
anything x2 = always evens
anything x3= odd, even, odd, even, odd, even (3, 6,9,12,)
anything x4=always even repeating last numbers (4, 8, 12, 16, 20, 24, 28, etc (48260)
anything x5= always ends in zero or five
anything x6= always evens repeating last numbers 6, 12, 18, 24, 30, 6, 42 (6,2,8,4,0)
anything x7= odd, even, odd even (7, 14, 21, 28)
anything x8= always evens (8, 16, 24, 32, 40) repeating (8,6,4,2,0)
anything x9= two tricks. one number goes up, the other down. 9, 18, 27, 36). Also--if you add the two digits together, they add up to 9--90, 81, 72, etc--only works to 10's. At 11's, you have to ignore both rules. At 12, they start back up--108, 117, 126, 135, etc
anything x10= add a zero to the end