Multiplication and Division

NZ Level 3

Multiply various single and double digit numbers

Lesson

There are many ways to solve multiplication problems, so having a little toolkit to call on is a great help. Some of the methods you may wish to use include:

- using arrays
- the area model of multiplication
- repeated addition
- using place value to break problems up
- breaking a problem into several smaller problems
- using the distributive property of multiplication
- using a vertical algorithm, or setting out your work down the page

Often you will find one method seems more suitable, depending on the type of the problem you are working on. Let's work through some problems in our videos. In Video 1, we multiply a $1$1 digit number by a $2$2 digit number, and see how we can use some of these methods.

When our numbers have $2$2 digits, we can still use the same methods, so in Video 2, we look at $2$2 digit numbers to see how things change. We can see how the area method of multiplication is really useful here, it just has more rectangles.

When we multiply $3$3 and $4$4 digit numbers, methods such as long multiplication, or splitting our number, may make more sense to use. Some of the other strategies above area still useful though! Let's work through some in Video 3.

Remember!

The method you use depends on what your problem looks like, but you might also find more than one method works. You can always solve one problem two different ways, to see which you find easier.

Find $22\times8$22×8.

Find $11\times125$11×125.

Find $7\times32\times8$7×32×8.

Record and interpret additive and simple multiplicative strategies, using words, diagrams, and symbols, with an understanding of equality