Alicia deposited $41 into her checking account. She wrote checks for $31 and $13. Now her account ha

Alicia deposited $41 into her checking account. She wrote checks for $31 and $13. Now her account has a balance of $81. How much did she have in her account to start with?

We start with a balance of b.

Depositing 41 means we add to the account balance:
b + 41

Writing checks for 31 and 13 means we subtract from the account balance:
b + 41 - 31 - 13

The final balance is 81, so we set b + 41 - 31 - 13 equal to 81:
b + 41 - 31 - 13 = 81

To solve for b, we type this equation into our math engine and we get:
b = 84