A positive two-digit integer ab is a multiple of a+b. How many such integers are there?
10 , 12 , 18 , 20 , 21 , 24 , 27 , 30 , 36 , 40 , 42 , 45 , 48 , 50 , 54 , 60 , 63 , 70 , 72 , 80 , 81 , 84 , 90 , Total = 23 such numbers
+407 
