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Prime factors

Mathematics

Prime factors

An AR classroom game for Grade 5. Learners can aim with their hands at the camera or play by tapping the screen.

This set has 6 questions in an interactive multiple choice activity.

Curriculum indicatorค 1.1 ป.5/1

PlayHost a classroom

A look before you play

Sample questions

A few real prompts from the game to help you choose an activity for your class.

  1. What is the prime factorisation of 12?

    • 2 × 2 × 3
    • 1 × 2 × 6
    • 1 × 3 × 4
    Read the explanation

    Twelve is two times two times three.

  2. What is the prime factorisation of 18?

    • 3 × 3 × 3
    • 2 × 3 × 3
    • 1 × 2 × 9
    Read the explanation

    Eighteen is two times three times three.

  3. What is the highest common factor of 12 and 18?

    • 12
    • 3
    • 6
    Read the explanation

    The common factors are one, two, three and six; the highest is six.

Before you play

Game teaching guide

What children will practise

Write the prime factorisations of 12, 18 and 20, spot a prime number, and find the HCF and LCM of two numbers, the groundwork for ค 1.1 ป.6/4-5.

What's in the worksheet

6 questions, multiple choice with 3 options - Prime factorisation of 12 (2 × 2 × 3) - Prime factorisation of 18 (2 × 3 × 3) - HCF of 12 and 18 (6) - LCM of 6 and 8 (24) - Which is prime: 27, 29 or 33 (29)

How to use it in class

Use after teaching factor trees; about 6 minutes. - Play solo, then put Q3 and Q4 on screen and explain by listing factors and multiples side by side - For Q1, Q2 and Q6, point out that options containing 1 are not prime factorisations, since 1 is not prime - If many miss Q4, count in 8s (8, 16, 24) and see which is also in the 6 times table - Play it linked to the class to record results in the mark book.

Common sticking points

- Q4: children often pick 48 (6 × 8), thinking the LCM is the product - Q3: HCF and LCM get mixed up, or children stop at the first common factor, 3 - Q1: 1 × 2 × 6 looks right because it makes 12, but 6 is not prime - Q5: 27 may be chosen for being odd; check with 3 × 9

Play together first, then build on it with a worksheet for the same level.

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