Using Area Model for Multi-digit Multiplication
Practice using the area model with this tool. Keep track of your work in your math journal. Scroll down to Fourth Grade Multiplication and Division. Then click on Multiplication: Open Arrays and go to View Teacher Tool.
Partial Products Multiplication
Watch this video explaining another strategy for multi-digit multiplication called partial products strategy.
You may replay the video as much as you need to be sure you understand the strategy and the thinking behind it.
1. Create several 2-digit practice problems to use this strategy. The factors must be greater than 10, and may not be multiples of ten.
2. Working with a partner or in a small group, solve the problems using the strategy.
3. Double check your work for accuracy by using a second solution strategy.
4.Prepare a way to explain the thinking behind this strategy. Why does this strategy work? What visual model can you create for this strategy? (poster, drawing, video, manipulatives, etc…)
5. Create a presentation to teach people about this strategy. This should not be just explaining the steps or the procedures. You should be showing the thinking behind the strategy and why it works.
Watch this video showing the traditional algorithm for multiplication.
Now solve the same problem (36 X 42) using the area model. Working together with group members, compare the two strategies. How are they related to one another? Which method do you think is most efficient?
Create three more 2-digit by 2-digit multiplication problems and solve them using the traditional algorithm. Check your process and answers with your group.
Prepare a poster to show the traditional algorithm. Be prepared to explain the relationship between the area model with the traditional Method.
2 Digit Multiplication
1. Create 3 practice problems to use this strategy. The numbers must be greater than 12 and not multiples of 10.
2. Check your work with a partner.
3. Create a word problem that would require you to use 2-digit by 2-digit multiplication to find the solution. Solve your problem and then have a partner solve it as well.
4. Working together, prepare a poster to teach this strategy to the class.
AREA AND PERIMETER OF IRREGULAR SHAPES
Watch this video to show you how to find the area and perimeter of irregular shapes. It does move rather quickly, so feel free to watch and rewatch the video as often as you’d like so you can catch all of the steps. Come to class tomorrow ready to do some practice problems.