Emma and Jason sell cupcakes at a bake sale. Every tray, Emma bakes 3 cupcakes and Jason bakes 2. Write the ratio of the number of Emma's cupcakes to the number of Jason's cupcakes.
Emma : Jason = 3 : 2
Ans: 3 : 2
Example 1
Emma, Jason and Maya bake trays of cupcakes. Every tray, Emma bakes 3 cupcakes, Jason bakes 2 and Maya bakes 4. Write the ratio of the number of Emma's cupcakes to the number of Jason's cupcakes to the number of Maya's cupcakes.
Emma : Jason : Maya = 3 : 2 : 4
Ans: 3 : 2 : 4
How to solve it
Name the quantities in the order the question gives them: Emma's cupcakes first, then Jason's.
Write the numbers in the same order with a colon, 3 : 2, and read it as 3 to 2.
A ratio compares and does not count: 6 cupcakes and 4 cupcakes are still 3 to 2.
Swap the order and the ratio changes: Jason's cupcakes to Emma's is 2 to 3, on its own line.
With three names, keep the order: Emma, then Jason, then Maya, is 3 to 2 to 4.
For every 3 of Emma's cupcakes, there are 2 of Jason's and 4 of Maya's. The names are in one order, and the numbers are in the same order.
Practice questions with worked solutions
Question 1 is free to try. The other 7 open in the free trial, each with its full working.
This page is the first step in the Primary 6 Ratio chapter.
What your child learns here
This page is the first step in the Primary 6 Ratio chapter. It teaches how a ratio is written and read, so that every later page, from sharing to before-and-after problems, starts from the right comparison.
Read and write ratios in the form a : b and a : b : c, using whole numbers.
Keep the numbers in the same order as the names the question gives.
Understand that a ratio compares quantities; it does not tell you how many there are.
Find the ratio of two or three given quantities, counting any quantity the question leaves out first.
Does the answer make sense?
Your child's answer should have one number for each thing the question names, in the same order as the names appear. When the total is one of the things named, as with the netball squad, its number must be the biggest in the ratio.
How to practise these questions
Basic questions train writing a ratio in the order the question names the quantities. Intermediate questions add a quantity left unstated, such as the rest, or a ratio of one part to the whole. Challenge questions use longer descriptions where the order must be read carefully. When writing a ratio in order is tricky, read the written step-by-step solution.
Questions parents ask
Is writing a ratio in the Primary 6 syllabus? Yes. The MOE Primary 6 syllabus lists the notation, representations and interpretation of a : b and a : b : c, where a, b and c are whole numbers, and finding the ratio of two or three given quantities. Ratios with fractions or decimals inside them are excluded at this level.
Is 3 : 4 the same as 4 : 3? No. The order of the numbers follows the order of the names, so swapping them changes what the ratio says. For apples to pears, 3 : 4 means fewer apples than pears, and 4 : 3 means more.
Does a ratio of 2 : 5 mean there are 7 things altogether? Not necessarily. A ratio compares; it does not count. 2 : 5 could be 2 and 5, or 20 and 50, so the total could be 7, 70 or any other multiple of 7.
