NZ Level 5
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Problem solving with decimals (mult/div)

What is our number problem?

When we solve written problems, we have to look for clues, such as key words and values, to work out what we need to solve. We have looked at solving problems with whole numbers, so we can take a similar approach with decimals.

In this short video, you can see some of the words you might find in problems and what it means. 


Multiplying with decimals

When we multiply with decimals, it really helps to think about what we need to do to solve our number problems. By remembering that decimals are a different way to express a number to fractions, we can use them to solve problems. Let's look at some examples where we may need to multiply with decimals.


Division with decimals

Let's work through some problems that require us to use division to write our number problem. The process is the same but we have to think about what we know and what we need to find out.


Worked examples

Question 1

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

Question 2

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

Question 3

Beth ordered some take away dinner for her family. She bought $4$4 main-course meals that cost $\$11.20$$11.20 each, and $4$4 entrees that cost $\$6.50$$6.50 each.

How much in total did the $4$4 main courses cost?



Understand operations on fractions, decimals, percentages, and integers

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