7. Decimal operations

Lesson

Let's review how to multiply and divide with decimals.

Find 43\times 1.06, giving your answer as a decimal.

Worked Solution

Find the value of 92.4\div6.

Worked Solution

Idea summary

We can use the vertical algorithm to multiply a decimal by a whole number. First we multiply the numbers without the decimal point. Then we include the decimal point so that the answer has the same number of decimal places as the question.

We can divide a decimal by a whole number using short division.

This video looks at how to interpret the story problem and identify the mathematics for a problem requiring multiplication.

A landscaper is paving a garden path with tiles that each have a mass of 7.18 kg. If he uses 7 tiles, what is the total mass?

Worked Solution

Idea summary

If we need to work out groups of something, it means we will need to use multiplication.

This video looks at how to interpret the story problem and identify the mathematics for a problem requiring division.

A TV series goes for a total duration of 13 hours. If there are 4 episodes in the series, all of equal length, how long is each episode? Give your answer in hours.

Worked Solution

Idea summary

If we are sharing and amount, then we will need to use division.

This video works through a story problem that involves division and subtraction.

Adam was buying supplies for the new school year. He bought 5 books at \$14.82 each and a pencil case for \$6.36. How much did he spend in total?

Worked Solution

Idea summary

When we have a story problem, there can be things that are not useful, so we need to make sure we find the right information.

compares, orders and calculates with fractions, decimals and percentages