PowerPoint created by Parsheena Berch Resource: JBHM material Pictures: Google Images

Whole Number and Decimal Operations

Bell Ringer: Page 21 in JBHM binder (DOK1)

Introduction/Focus: Adding and subtracting decimals What if you had $100.00 and wanted to spend $23.48, but you wanted to know how much money you had left? You must be able to subtract decimal numbers in order to get an answer. There are many times we need to add and/or subtract decimals.

Guided Practice: Adding and Subtracting Decimals: To add and subtract decimals, use the same process you use to add and subtract whole numbers except the decimal points must be aligned. Strategy: line up the decimals points and fill in with zeros. Turn to page 47.

Examples: Incorrect Correct 3.129 3.129 +34.261 +34.261 415.326 415.326 - 41.23 -41.23

Example: 2.167 + 32.104 Be sure to line up the decimals!!!

Example: 3.44 – 0.538 Again, line up the decimals and fill in with zeros!!!

Application Problem: The bill for repairs to your computer ran $24.56 for a new keyboard, $12.95 for a new mouse, and $50 for labor. What is the cost of your computer repair bill?

Independent Work/Activity: (DOK3) I am going to give you three numbers. You must arrange the numbers in an addition or subtraction decimal sentence so the number make a true sentence. You will have one minute to arrange your numbers, and write the problem down and work it!!!

Closure: Who can explain the process of adding or subtracting decimals?