The number "1A" isThe number "2B" is So since "1A" + A = "2B", Add 10 to all three sides: So the different digits from 0 through 9 which A could represent are the five numbers 5,6,7,8,9 So the answer if five. If A=5, then B=2A-10 = 2(5)-10 = 10-10 = 0 15 +5 -- 20 If A=6, then B=2A-10 = 2(6)-10 = 12-10 = 2 16 +6 -- 22 If A=7, then B=2A-10 = 2(7)-10 = 14-10 = 4 17 +7 -- 24 If A=8, then B=2A-10 = 2(8)-10 = 16-10 = 6 18 +8 -- 26 If A=9, then B=2A-10 = 2(9)-10 = 18-10 = 8 19 +9 -- 28 Edwin