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

Lesson 4.3Estimate the Percent of a Number

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.

Why This Matters Margaret checked the cloud storage on her phone: 6 GB total, 4 GB used. Approximately what percent of her storage is used — and of the used storage, approximately what percent are photos?

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 example

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

A game download is 80 MB. 41 MB are done. About what percent is done?

  1. Whole: 80 MB is 100%.
  2. 50% of 80 is 40 MB.
  3. 41 MB is just over 40 MB.

Answer: about 50%

Now you trySame steps, your turn

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

The Green-Team recycled 216 pounds of material; 8.6% was metal.

Answer:

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 out!A common mistake

Keeping the same whole for every question

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

Lesson 4.3Estimate the Percent of a Number

Level 0Most support · every hint printed

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.

Why This Matters Margaret checked the cloud storage on her phone: 6 GB total, 4 GB used. Approximately what percent of her storage is used — and of the used storage, approximately what percent are photos?

How it worksWorked example

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

A game download is 80 MB. 41 MB are done. About what percent is done?

  1. Whole: 80 MB is 100%.
  2. 50% of 80 is 40 MB.
  3. 41 MB is just over 40 MB.

Answer: about 50%

  1. 1Circle the letter of the best answer. Show how you know.

    Margaret's phone has 6 GB of storage and 4 GB is used. About what percent is used?

    1. AAbout 25%
    2. BAbout 40%
    3. CAbout 70%
    4. DAbout 150%
    Steps to try
    1. What is the whole?
    2. 4 out of 6 is the same as 2 out of 3.
    3. Two-thirds is close to which benchmark?
    Show your work
  2. 2Circle the letter of the best answer. Show how you know.

    On the double number line for 6 GB, what amount lines up with 25%?

    1. A1.25 GB
    2. B1.5 GB
    3. C2.5 GB
    4. D4 GB
    Steps to try
    1. 25% means one quarter.
    2. One quarter of 6.
    3. 6 ÷ 4.
    0%50%100%
    Work
    1. 1Whole100% is what number?
    2. 2Find 10%Divide by 10.
    3. 3BuildAdd or multiply to the percent.
    4. 4CheckIs it under or over the whole?
  3. 3Circle the letter of the best answer. Show how you know.

    Which benchmark percents make good landmarks on a number line?

    1. A0%, 25%, 50%, 75%, 100%
    2. B3%, 17%, 62%, 94%
    3. COnly 50%
    4. DOnly 100%
    Steps to try
    1. Which percents can you find mentally?
    2. Quarters and tenths are the friendly ones.
    3. 0, 25, 50, 75, 100.
    Show your work
  4. 4Circle the letter of the best answer. Show how you know.

    To estimate 8.6% of 216 by rounding, which numbers should you use?

    1. A1% of 216
    2. B8% of 300
    3. C10% of 220
    4. D86% of 216
    Steps to try
    1. Round each number to something friendly.
    2. 8.6% is close to which benchmark?
    3. 216 is close to which round number?
    Show your work

Explain your thinkingYou sorted a move into 'Benchmark percent' and your partner into 'Compatible numbers.' Which number did each strategy change — the percent or the whole — and why does changing that one keep the estimate close?

Sentence starter This is ___ because it changes the ___, and the estimate stays close since ___.

3-Point Exit Checklist: ☐ 1. Units & Labels Verified ☐ 2. Mathematical Reasoning Stated ☐ 3. Calculations Double-Checked
How did it go? ☐ 4 · I can teach it☐ 3 · I've got it☐ 2 · I need a hint☐ 1 · I need help