Subtracting Decimals
Part of the Decimals, Percents & Ratios section of Coddy's Pre-Algebra journey. Lesson 7 of 56.
Subtracting works the same way: line up the points and pad with zeros. A whole number has a decimal point too, hidden at its end, so 9 is 9.00. Then 9 - 2.35 becomes a column subtraction:
9.00 - 2.35 = 6.65
The hundredths need 0 - 5, so borrow: one of the 9 ones becomes 10 tenths, and one of those tenths becomes 10 hundredths. Then 10 - 5 = 5 hundredths, 9 - 3 = 6 tenths and 8 - 2 = 6 ones. The answer is 6.65.
The zeros are the key move. Without them it is tempting to bring the 35 hundredths straight down into the answer, which subtracts them from nothing. To check, add back what you took away: 6.65 + 2.35 is 9.
Challenge
Work out 8 - 3.45. Give 8 its hidden decimal point and zeros first.
Try it yourself
Simplify the expression
Test yourselfThis lesson includes a short quiz. Start the lesson to answer it and track your progress.
All lessons in Decimals, Percents & Ratios
4Dividing Decimals
Dividing by a DecimalDividing by 10 and 100Dividing by a Whole NumberUnit PriceRecap: Dividing2Adding Decimals
Adding DecimalsSubtracting DecimalsNegative DecimalsMaking ChangeRecap: Add and Subtract