Have a look at the tens column, if C+A=C, then A = 0, that's if nothing was carried from the units column.
ADCB + DTAF = TTHCE. Using the numbers 0-7, what do A,B,C,D,E,F,H, and T represent? Each number may only be used to represent one unknown. There are eight unknowns, so all numbers must be used.
This is for extra credit. I know that T must be 1, so that the sum of the two numbers is 11000 something. Other than that I'm stumped, any help please?