Byong Su withdraws $18 from his bank account once each day for five days. What integer

Byong Su withdraws $18 from his bank account once each day for five days. What integer represents the change in the amount in the account? Use pencil and paper. Find the integer that would represent the change in the amount in the account if Byong Su deposits $18 into his bank account once each day for five days. Explain the difference between the integer for the withdrawals and the integer for the deposits.