Carter has saved $27.50 of his allowance money
that means He have total amount = $27.50
He bought his sister ice cream for $3.75
that means He spend an amount = $3.75
The amount he left is the difference between the amount he has total with the amount he spend on icecream
The amount he left is = $27.50-$3.75
Amount he left = $23.75
Answer : $23.75