Decimals - Multiplying

5th Grade Standard

5.NBT.B.7 Add, subtract, multiply, and divide decimals to hundredths, using concrete models or drawings and strategies based on place value, properties of operations, and/or the relationship between addition and subtraction; relate the strategy to a written method and explain the reasoning used.

Strategies for Multiplying Decimals - Go Math Lesson Guides

Below are some videos to accompany the lessons in Chapter 6 - Multiply Decimals and Whole Numbers and Chapter 7 Multiply Decimals (These videos were from older versions that refer to Ch. 4 but are the same lessons, they are now in Chapters 6 and 7.

Lesson 6.1 - Understand Decimal Multiplication Patterns

Lesson 6.1 -Understand Decimal Multiplication Patterns

Lesson 6.2 - Represent Multiplication with Decimals and Whole Numbers

Lesson 6.3 - Multiplication with Decimals and Whole Numbers - This video goes into more detail on the strategies used in 6.3 - when figuring out how to place the decimal she calls it "hops"

Lesson 6.3 - Multiplication with Decimals and Whole Numbers - Here is a short and sweet explanation of the strategies in the lesson. He uses different terminology for learning how to place the decimal - he calls it moving "2 decimals"

Lesson 6.4 - Multiply Using Expanded Form

Lesson 6.5 - Multiply Money

Here is a good example of using area model to multiply with decimals.

This video reinforces the model but also ties it to the written method and explains the decimals places. So it gives a quick but nice overall explanation.

This video is long (18 minutes) but it has some good explanation in it. It uses area model with expanded form rather than visual drawing models as in the previous videos, which can go quicker but still breaks it down from a traditional algorithm. Helps students to see what is going on in the process but not have to draw everything out but still show their thinking in a model. I also like how she talks everything through using consistent language. She gives several examples, including a word problem and then has a couple at the end which she doesn't work through. This would be a good one to stop several times throughout the video and see if you can answer it before watching her work it out.