MathsYear 6Algebra

Find unknowns in equations

Express missing number problems algebraically; find pairs of numbers that satisfy an equation with two unknowns; enumerate possibilities of combinations of two variables

What you'll learn

  1. 1

    Imagine you have 12 sweets in a bag. You take out 5 and eat them. How many are left in the bag? That's 12 − 5 = ?

  2. 2

    In 12 − 5 = ?, what is the unknown?

  3. 3

    Use the number line to find the missing number: 8 + ? = 15. Jump from 8 to 15 — how many steps?

  4. 4

    Let's find the missing number in 25 + ? = 40.

  5. 5

    What is the missing number in this equation? 30 − ? = 12

  6. 6

    What is the missing number? 7 × ? = 56

  7. 7

    Now try this: ? + 14 = 32. Use the number line to find the answer.

Practise Find unknowns in equations with Whizlo

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