Learning Goal: Learn what a ratio is and how to describe a relationship between two amounts using ratio language.
Vocabulary
ratioA way to compare two amounts. Example: 3 cats to 2 dogs.
termOne of the two numbers being compared in a ratio.
part-to-partA ratio that compares one group to another group, like boys to girls.
part-to-wholeA ratio that compares one group to the total, like boys to all students.
What You Need to Know
A ratio compares two amounts. You can write it 3 ways: 3 to 2, 3:2, or 3/2.
Order matters. The ratio 3:2 is not the same as 2:3.
Part-to-part compares two groups (red marbles to blue marbles).
Part-to-whole compares one group to the total (red marbles to all marbles).
If there are 4 red and 5 blue marbles, there are 9 in all. Red to total is 4:9.
Always include the units or labels when you describe a ratio in words.
Worked Example I Do — watch how it works
A fruit bowl has 6 apples and 4 oranges. Write the ratio of apples to oranges, and the ratio of apples to all fruit.
Step 1. Count each group: 6 apples and 4 oranges.
Step 2. Apples to oranges is a part-to-part ratio: 6 to 4, or 6:4.
Step 3. Find the total: 6 + 4 = 10 pieces of fruit.
Step 4. Apples to all fruit is a part-to-whole ratio: 6 to 10, or 6:10.
Answer: Apples to oranges = 6:4. Apples to all fruit = 6:10.
Guided Practice We Do — try it together
1. A team has 7 forwards and 5 defenders. Write the ratio of forwards to defenders.
💡 Hint: Write the first amount first. Forwards come first.
2. A box has 3 red pens and 8 blue pens. Write the ratio of red pens to all pens.
💡 Hint: Add to get the total first: 3 + 8.
3. In a class there are 9 boys and 12 girls. Write the ratio of girls to boys.
💡 Hint: Girls come first, so write 12 first.
Independent Practice You Do — show your work
1. A garden has 5 roses and 8 tulips. Write the ratio of roses to tulips.
2. A snack mix has 10 peanuts and 6 raisins. Write the ratio of raisins to peanuts.
3. A bag has 4 green and 7 yellow markers. Write the ratio of green markers to all markers.
4. A parking lot has 15 cars and 5 trucks. Write the ratio of trucks to all vehicles.
5. True or false: the ratio 2:5 means the same thing as 5:2.
MCAP-Style Practice
Directions: Answer each item the way you would on the MCAP. For selected-response items, fill in the circle (○) next to the correct answer. For constructed-response items, enter your answer and show your work. Every item below assesses standard 6.RP.A.1.
Item 1Selected Response6.RP.A.1
A tank has 8 goldfish and 3 guppies. What is the ratio of guppies to goldfish?
Select the correct answer.
Item 2Selected Response6.RP.A.1
A choir has 6 sopranos and 9 altos. Which statement is correct?
Select the correct answer.
Item 3Constructed Response6.RP.A.1
A bowl has 5 limes and 7 lemons. Write the ratio of lemons to limes using a colon.
Enter your answer in the space provided. Show your work.
Enter your answer:
Teacher Answer Key (click to show)
Independent 1
5:8
Independent 2
6:10
Independent 3
4:11
Independent 4
5:20
Independent 5
False (order matters)
Item 1 · 6.RP.A.1
B — Guppies come first (3), then goldfish (8).
Item 2 · 6.RP.A.1
B — Total is 6+9=15, so altos to total is 9:15.
Item 3 · 6.RP.A.1
7:5 — Lemons (7) first, then limes (5).
Neft Teacher · Grade 6 MCAP Mathematics Review · Standard 6.RP.A.1