3. Multiplication and division
PRACTICE: Multiplication and Division
Lesson
Practice
Let's go over some of the multiplication and division strategies and problems we've looked at. These include:
- using arrays and area models
- partitioning numbers by place value
- using a standard algorithm
We also looked at using a standard algorithm to solve multiplication or division, for larger numbers. This strategy is useful if we need to trade, or regroup.
Apply
QUESTION 1
Let's use the area model to find $29\times28$29×28.
Fill in the areas of each rectangle.
$20$20 $9$9 $20$20 $\editable{}$ $\editable{}$ $8$8 $\editable{}$ $\editable{}$ Find the sums of each column
$20$20 $9$9 $20$20 $400$400 $180$180 $8$8 $160$160 $72$72 Total: $\editable{}$ $\editable{}$ What is the total area of the rectangles?
$20$20 $9$9 $28$28 $560$560 $252$252 So what is $29\times28$29×28?
QUESTION 2
Find the value of $651\div7$651÷7.
QUESTION 3
Find the value of $297\div16$297÷16.
$\editable{}$ with remainder $\editable{}$
Remember!
Arrays and the area model are great to solve multiplication or division problems when there will be no remainder. If we are not sure, we can use a standard algorithm.