Learning Goal: Find a percent of a number, and find the whole when you know a part and its percent.
Vocabulary
percentA part out of 100. The symbol is %.
partThe piece of the whole that the percent describes.
wholeThe full 100% amount.
What You Need to Know
Percent means 'out of 100.' So 25% = 25 out of 100 = 0.25.
To find a percent of a number, change the percent to a decimal and multiply.
Example: 15% of 60 = 0.15 × 60 = 9.
10% is an easy benchmark: just move the decimal one place left.
To find the whole from a part, divide the part by the percent (as a decimal).
Example: if 9 is 25%, the whole is 9 ÷ 0.25 = 36.
Worked Example I Do — watch how it works
A jacket is on sale for 30% off. The discount is $24. What was the original price?
Step 1. The part (discount) is $24 and the percent is 30%.
Step 2. To find the whole, divide the part by the percent as a decimal: 24 ÷ 0.30.
Step 3. 24 ÷ 0.30 = 80.
Answer: $80 original price
Guided Practice We Do — try it together
1. What is 20% of 45?
💡 Hint: Change 20% to 0.20, then multiply by 45.
2. 12 is 25% of what number?
💡 Hint: Divide the part by the decimal: 12 ÷ 0.25.
3. A class of 30 students has 40% wearing glasses. How many wear glasses?
💡 Hint: Find 40% of 30: 0.40 × 30.
Independent Practice You Do — show your work
1. What is 15% of 80?
2. What is 50% of 96?
3. 18 is 30% of what number?
4. A $40 meal has a 20% tip added. How much is the tip?
5. A team won 75% of its games and won 15 games. How many games did it play?
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.3c.
Item 1Selected Response6.RP.A.3c
What is 35% of 200?
Select the correct answer.
Item 2Selected Response6.RP.A.3c
A shirt is 60% of the way sold out. 24 shirts are sold. How many shirts were there at the start?
Select the correct answer.
Item 3Constructed Response6.RP.A.3c
In a survey, 45 students said yes. That was 25% of all students. Fill in: there were ____ students in all.
Enter your answer in the space provided. Show your work.
Enter your answer:
Teacher Answer Key (click to show)
Independent 1
12
Independent 2
48
Independent 3
60
Independent 4
$8
Independent 5
20 games
Item 1 · 6.RP.A.3c
B — 0.35 × 200 = 70.
Item 2 · 6.RP.A.3c
C — 24 ÷ 0.60 = 40 shirts.
Item 3 · 6.RP.A.3c
180 — 45 ÷ 0.25 = 180 students.
Neft Teacher · Grade 6 MCAP Mathematics Review · Standard 6.RP.A.3c