Question

Reasoning Miriam withdraws $18 from her bank account once each day for four 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 Miriam deposits $18 into her bank account
once each day for four days. Explain the difference between the integer for the withdrawals and the
integer for the deposits.
The integer represents the change in the amount in the account after withdrawing $18 once each
day for four days.

Answer 1

Miriam's bank account changes by -72 when she withdraws $18 for four days and by +72 when she deposits $18 for the same period, reflecting the respective decreases and increases in her account balance.

Step-by-step explanation:

When Miriam withdraws $18 from her bank account once each day for four days, the total amount withdrawn is $18 × 4 = $72. The integer representing the change in the account for the withdrawals is -72, as money is being taken out of the account.

If Miriam instead deposits $18 into her bank account once each day for four days, the total amount deposited would also be $18 × 4 = $72. In this case, the integer representing the change in the account for the deposits is +72, because money is being added to the account.

The difference between the integers is the sign. Withdrawals represent a decrease in account balance, thus a negative integer is used. Deposits represent an increase in account balance, leading to the use of a positive integer.