Lesson

When we need to solve multiplication problems, we have many methods we could use. Which method we choose depends on our problem, how many digits our numbers have, and the method we are more comfortable with.

Idea summary

Methods used in multiplication:

repeated addition

double-double

area model

partitioning by place value

partitioning by factors

vertical multiplication

Let's look at a video on how to multiply two 2 digit numbers.

Calculate 26 \times 39 by completing an area model.

a

Firstly, complete the missing values in the area model.

\times | 20 | 6 |
---|---|---|

30 | ||

9 |

Worked Solution

b

Now add the values you found in part (a) to calculate 26\times 39.

Worked Solution

Idea summary

We can use area models to multiply 2 two digit numbers.

This video looks at using the algorithm to solve a multiplication problem.

Find 7\times 583.

Worked Solution

Idea summary

There isn't one perfect way to solve multiplication problems. The best approach is to have a range of methods to choose from, so you can choose the method that suits the problem. This is just like having a toolkit with different tools.

Select and apply efficient mental and written strategies and appropriate digital technologies to solve problems involving all four operations with whole numbers and make estimates for these computations