Scaling problem
A ribbon 4 times as long as 6 cm is 24 cm long.
Scaling compares one amount with a larger multiple of it.
Year 4
Solve problems involving multiplying and adding, including integer scaling problems and harder correspondence problems such as n objects are connected to m objects
Use multiplication and division to solve scaling, grouping and correspondence problems, and decide what the numbers mean in context.
Lesson overview
Number - multiplication and division
Some multiplication problems are about equal groups, some are about scaling up, and some are about combinations or links. Reading the context carefully helps decide which operation fits and what the answer means.
Equal groups
5 boxes with 8 pencils in each box hold 40 pencils altogether.
Equal groups usually point to multiplication.
Correspondence
3 shirts and 2 pairs of trousers make 6 different outfits.
Each item can connect with more than one choice.
Worked example
A toy car has 4 wheels. How many wheels do 9 toy cars have?
- Each car has the same number of wheels.
- That means this is an equal-groups multiplication problem.
- 9 x 4 = 36.
- So 9 toy cars have 36 wheels.
Round 1: Learn it
Use the wording to decide whether the problem is about groups, scaling or combinations.
Finish this round to unlock Round 2: Show you know it.
Question 1
There are 6 packs with 7 stickers in each pack. How many stickers are there?
Question 2
A rope is 5 times as long as a 4 m piece. How long is it?
Question 3
4 hats and 3 scarves can make how many outfit combinations?
Question 4
Which operation best fits '3 rows of 8'?
Question 5
Which answer is correct for 7 trays with 6 buns on each tray?
Common mistakes
Watch for these as you work through the lesson.
- Choosing the wrong operation from the story.
- Missing that one item can link with several others in a correspondence problem.
- Solving the calculation but not checking whether the answer fits the context.
Related topics
These ideas connect closely to this lesson.
- Recall multiplication and division facts for multiplication tables up to 12 x 12.
- Multiply two-digit and three-digit numbers by a one-digit number using formal written layout.