Brian's 100-yard dash time was 2.68 seconds more than one school record. Brian's time was 13.4 seconds. What is the school record?
The school record is less than Brian's time. Thus, 2.68 must be subtracted from 13.4; 13.4 - 2.68 = 10.72. To subtract decimals, line up the numbers vertically so in which the decimal points are aligned. Because 13.4 has one less decimal place than 2.68, you must add a zero after the 4 (13.40) before subtracting. After you have completed this, subtract generally.