Step-by-step explanation: You can assume the A is less than B, and if you just go down in numbers such as A=6 and B=7 (To solve A + B = 13), you will eventually get to A=5 and B=8. If you do B = 8 + C = 14 ( That you get after subtracting 8 by 22 ) You should get 22, and to proof check it, you do A + C which is going to be 5 + 14 and you get 19 thus proving that C = 14.