First convert 22 to decimal form. You do this by dividing the percent by 100.
22 / 100 = .22
Then multiply the dollar amount by the percentage in decimal form.
$45 * .22 = $9.9
So 22% of $45 is $9.9.
Then you subtract $9.9 from $45.
$45 - $9.9 = $35.1
