A ratio compares two amounts of the same kind. If a fruit bowl has 4 apples and 6 oranges, the ratio of apples to oranges is 4 to 6. Ratios can be written three ways: with the word “to” (4 to 6), with a colon (4:6), or as a fraction (4/6). Order matters —“apples to oranges” is not the same as “oranges to apples.”
Lesson alignment: 6.RP.A.1 · Take your time. You can return to this lesson whenever you need it.
Explore visually
Compare parts in a ratio
Change the two amounts, then compare apples with oranges or compare one part with the whole group.
Think first: If you reverse the order, what changes in the comparison? What changes when a part is compared with the whole?
Ready? Reveal the model and try your prediction
Swipe horizontally to see the full diagram.
Turn on JavaScript to adjust this model. The examples and practice below work without it.
Follow the worked examples
Read each step, then cover the explanation and see if you can explain why it works.
Worked example 1
A classroom has 12 boys and 15 girls. Write the ratio of boys to girls in three different ways and simplify it.
Write the comparison in the order asked —boys to girls, so boys come first: 12 to 15, 12:15, or 12/15. To simplify, find the GCF of 12 and 15, which is 3. Divide both parts: 12 ÷ 3 = 4 and 15 ÷ 3 = 5. The simplified ratio is 4:5.
Answer: 12:15 = 4:5
Worked example 2
A recipe uses 3 cups of flour for every 2 cups of sugar. What is the ratio of sugar to the total amount of flour and sugar?
This is a part-to-whole ratio, so first find the whole. Total cups = 3 + 2 = 5. Sugar (the part we want) is 2 cups. So the ratio of sugar to the whole mixture is 2:5. It is already simplified because 2 and 5 share no factor besides 1.
Answer: 2:5
Try a few on your own
Work these on paper first. Open “Check” when you are ready to compare your answer.
6 : 9 =Check
2:3
8 : 12 =Check
2:3
10 : 25 =Check
2:5
14 : 21 =Check
2:3
18 : 24 =Check
3:4
20 : 35 =Check
4:7
15 : 45 =Check
1:3
32 : 48 =Check
2:3
Try this situation 1
In Ms. Garcia's class there are 10 students who walk to school and 15 who take the bus. Write the ratio of walkers to bus riders in simplest form, and the ratio of walkers to the total number of students.
Show a worked solution
Answer: Walkers : bus riders = 2:3; walkers : total = 2:5.
Walkers : bus riders is 10:15. Divide both by 5 to get 2:3. The total is 10 + 15 = 25 students, so walkers : total is 10:25 = 2:5.
Try this situation 2
A pet store has 24 goldfish and 32 guppies. Marcus says the ratio of goldfish to guppies is 3:4. Is he right? Explain.
Show a worked solution
Answer: Yes. 24:32 simplifies to 3:4.
Find the GCF of 24 and 32, which is 8. Divide both: 24 ÷ 8 = 3 and 32 ÷ 8 = 4, giving 3:4. Marcus is correct.
Fresh questions · saved on this device
Practice this skill
44 question pool
Try a fresh set each time. Answer one question, check your thinking, and read the explanation. If you miss one, return to the visual model and try another round.
Question 1 of 50 correct so far
Session complete
Check what you learned
Answer these five questions on your own. You can review the explanations after you submit and try again whenever you like. This short check is for practice, not a grade.
Practice and finish
Try the linked topic quiz for more practice. If something is tricky, return to the example and look for the step that changes the numbers or representation.
Your checkmark, skill-practice sessions, and best exit-check score are saved on this browser and device. The course page can download a progress report to share with a tutor or teacher.
More Grade 6 resources
Use these free materials if you want another explanation, extra paper practice, or a broader review.