Astudent's checking account contained $660 at the beginning of the month. the student had five transactions during the month: deposited $347, withdrew $256, withdrew $120, deposited $393, and withdrew $250. what was the account balance at the end of the month?

First thing u must know is deposit is when the money goes in to your account which mean your money increases while withdraw is when your money goes out of your account which mean your money decreases. To conclude this

deposit means plus (+)
withdraw means minus (-)

Start with $660
The student then deposited $347, so
$660 + $347 = $1007
Then withdrew 256, so
$1007 - $256 = $751

Please remember that
deposit means plus the money (+)
withdraw means minus the money (-)

Continuing another 3 transactions with current money $751
The student then withdrew $120, so
$751 - $120 = $631

Same method goes to the rest of transaction
$631 + $393 = $1024
$1024 - $250 = $774

Finally the account balance after all those transaction will be $774