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Grade 4 Prime & Composite Numbers Worksheet with Answers

Grade 4 (US) · Year 5 (UK) · Class 4 (India) · Math

Unit 3: Factors, Patterns & Problem SolvingFactors & PrimesCCSS 4.OA.B.4

Deciding whether numbers up to 100 are prime or composite. This free upper elementary worksheet has 12 questions and a full answer key. Print it or save it as a PDF — every answer is checked by code, not guessed.

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Prime & Composite Numbers

Grade 4 · Math

Score___ / 12

Name

Class

Date

Learning goal: Factors & Primes · CCSS 4.OA.B.4

Directions: Solve each problem. Show your work, then write your answer in the box.

Example

Is 16 prime or composite?

Answer: composite

RememberFactors and primes

36218293336 = 2 × 2 × 3 × 3Prime: exactly 2 factors (2, 3, 5, 7, 11…)Composite: more than 2 factorsGCF: biggest factor both shareLCM: smallest multiple both share
  1. 1

    What is the smallest prime number greater than 83?

    Answer
  2. 2

    What is the smallest prime number greater than 14?

    Answer
  3. 3

    What is the smallest prime number greater than 53?

    Answer
  4. 4

    Is 13 prime or composite?

    PrimeComposite
  5. 5

    What is the smallest prime number greater than 39?

    Answer
  6. 6

    Is 51 prime or composite?

    PrimeComposite
  7. 7

    Is 42 prime or composite?

    PrimeComposite
  8. 8

    Is 3 prime or composite?

    PrimeComposite
  9. 9

    Is 58 prime or composite?

    PrimeComposite
  10. 10

    What is the smallest prime number greater than 35?

    Answer
  11. 11

    What is the smallest prime number greater than 61?

    Answer
  12. 12

    Is 53 prime or composite?

    PrimeComposite

★ Challenge corner for fast finishers

In this magic square every row, column and diagonal adds up to 102. Row 1: 25, ____, 31 | Row 2: 40, 34, 28 | Row 3: 37, 22, 43. What is the missing number?

2531403428372243

How did I do?

Teacher's comments

Free printable worksheets with answer keys · aethelsystems.com/worksheets/math/4/prime_composite

Answer key (click to show)
  1. 1.89
  2. 2.17
  3. 3.59
  4. 4.prime
  5. 5.41
  6. 6.composite
  7. 7.composite
  8. 8.prime
  9. 9.composite
  10. 10.37
  11. 11.67
  12. 12.prime
  13. ★46 (challenge corner)

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How to use this worksheet

  • Use it as a 10–15 minute warm-up or homework task rather than a long drill.
  • Ask students to show their working so you can see where a mistake started, not just that it happened.
  • Mark it with the answer key together, then print a fresh version of the same topic to practise the questions they missed.

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Guides for teaching Prime & Composite Numbers

Long Division Step by Step: An Easy Method (With Remainders)Divide, multiply, subtract, bring down — the four-step routine that makes long division manageable, with worked examples, remainders, zeros and two-digit divisors.What Are the Common Core and NGSS Standards? A Parent's GuideWhat learning standards are, how to read a code like 3.NF.A.1 or MS-PS1-2, what each grade covers in Math, English and Science, and how to use them at home.How to Help Your Child with Math Homework (Without Doing It for Them)Questions to ask instead of answers to give, what to do when the school's method looks different from yours, and how to handle frustration.

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