Grade 6 Mathematics · Unit 4: Understand and Use PercentagesStandard 6.AT.4

Lesson 4.34.3 Small Group · Group 2

Start hereWords, worked example, and sentence starters

Name Date Period

Learning target I can estimate the percent of a number using benchmark percents, rounding, and compatible numbers, explain why the method works, and use it on a problem I have not seen before.

Start hereWords for this lesson

Read each word before you begin. Say it out loud.

WordWhat it meansExample
estimateSpanish: estimación A reasoned answer that is close enough to be useful, found without exact computation. about 70% used
benchmark percentSpanish: porcentaje de referencia A friendly percent — 1%, 10%, 25%, 50%, 75%, 100% — used as a landmark for estimating. 10%, 25%, 50%, 75%
compatible numbersSpanish: números compatibles Numbers close to the originals that are easy to compute with mentally. 8.6% of 216 → 10% of 220: both nudged to numbers that divide nicely.
double number lineSpanish: recta numérica doble Two parallel number lines that pair amounts with their percents at the same positions. 0, 30, 60 GB over 0%, 50%
the wholeSpanish: el todo The quantity that counts as 100% in a problem — and it can change between questions. all of the storage
DecomposeSpanish: Descomponer Break a percent into friendly pieces that are easy to find. 15% = 10% + 5%

How it worksWorked exampleestimating a percent with benchmarks

These numbers are not on your problems. The steps are. Follow them with your own numbers.

A tablet holds 64 GB of storage and 47 GB are already used. About what percent of the tablet is full?

  1. Name the whole: all 64 GB stands for one hundred percent.
  2. Mark benchmarks: halfway is 32 GB, and three quarters of the way is 48 GB.
  3. Locate the used amount, 47 GB — it sits right at the three-quarter mark.
  4. Estimate with that benchmark, not with exact division.

Answer: About three quarters — roughly seventy-five percent — of the tablet is full.

Now you trySame steps, your turn

The steps are the same as the worked example. The numbers are yours. Do the work.

A water tank holds 80 L and has 22 L in it right now. About what percent of the tank is full?

  1. The whole is L, and it stands for one hundred percent.
  2. Half of the tank is L. One quarter of the tank is L.
  3. The amount 22 L sits closest to which benchmark?
  4. Estimate: about %
Answer:about what percent of the tank is full

Say it and write itSentence starters

Finish each sentence out loud with a partner. Then use them in your writing.

  • The whole in this problem is , so it stands for one hundred percent.
  • The benchmark closest to is .
  • My estimate is about % because .
  • I know my estimate is reasonable because .

Word bank estimateaboutbenchmarkwholepartdouble number linehalfone quarterthree quartersclose toreasonablecompare

Watch outA common mistake

Keeping the same whole for every question — when the problem says 'of the used storage,' the whole changes from 6 GB to 4 GB, and estimates anchored to the old whole are wrong before any arithmetic happens.

Grade 6 Mathematics · Unit 4: Understand and Use PercentagesStandard 6.AT.4

Lesson 4.34.3 Small Group · Group 2

Group 2Challenge practice

Mastery check☐ Exceeds☐ Meets target☐ Needs practice
Name Date Period

Learning target I can estimate the percent of a number using benchmark percents, rounding, and compatible numbers, explain why the method works, and use it on a problem I have not seen before.

  1. 1Complete each step, then write the final answer.
    Percent (%)1002575Books1,200??÷ ?÷ ?× ?× ?

    A library has 1,212 books. 77% of them are fiction. Estimate the number of fiction books. Is your estimate high or low?

    1. 1Round 77% and 1,212 to friendly numbers.
    2. 2Divide 100% and 1,200 by 4. How many books is 25%?
    3. 3Multiply 25% and 300 by 3. How many books is 75%?
    4. 4Both numbers were rounded down. Is 900 high or low?
    Final answer:
  2. 2Complete each step, then write the final answer.
    Percent (%)100515Meal ($)40??÷ ?÷ ?× ?× ?

    A meal costs $41.80. You want to leave a 15% tip. Estimate the tip.

    1. 1Round $41.80 to a friendly number.
    2. 2Divide 100% and $40 by 20. How much is 5%?
    3. 3Multiply 5% and $2 by 3. About how much is the tip?
    4. 4Is $6 a little high or a little low? Why?
    Final answer:
  3. 3Complete each step, then write the final answer.
    Percent (%)Number________________________

    Estimate 61% of 497. Combine benchmark percents.

    Show your work
    Final answer:
  4. 4Complete each step, then write the final answer.
    Percent (%)Number________________

    Estimate 11% of 516 with benchmarks. Is your estimate a little high or a little low?

    Show your work
    Final answer:
  5. 5Complete each step, then write the final answer.
    Percent (%)Seats________________

    A concert hall has 2,415 seats. On Friday, 49% of the seats were filled. About how many seats were filled?

    Show your work
    Final answer:
  6. 6Complete each step, then write the final answer.
    Percent (%)Number________________________

    Nia estimates 4.8% of 610. She says 10% of 600 is 60, so the answer is about 60. Find a better estimate.

    Show your work
    Final answer:

Explain your thinkingTwo friends estimate 26% of 395. One uses 25% of 400. One uses 30% of 400. Which estimate is closer? How do you choose a benchmark?

ChallengeWrite your own problem

Write a new word problem that uses this lesson's idea. Then solve it and show every step.

How did it go? ☐ 4 · I can teach it☐ 3 · I've got it☐ 2 · I need a hint☐ 1 · I need help