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Grade 6 · Maths · Lessons
One step to the answer
⚖️balance🔄undo➗divide➕add
One step.
The big ideaUndo the one operation, and do the same to both sides.

How it works

Undo the one operation, and do the same to both sides.

6 × ? = 48: undo times by dividing, 48 ÷ 6 = 8.

x + 1.75 = 2.55: undo adding by taking away: 2.55 − 1.75 = 0.80.

6x = 48• divide both sides by 6• x = 8x + 1.75 = 2.55• take 1.75 from both sides• x = 0.80
Keep the balance.

Example 1: A times

  1. 6 × ? = 48.
  2. Undo the times by dividing: 48 ÷ 6 = 8.
  3. The missing number is 8.

Example 2: A fraction

  1. 1/8 × ? = 3.
  2. Undo by dividing by 1/8, which is times 8: 3 × 8 = 24.
  3. The missing number is 24.

Example 3: An add

  1. Ava had some water and poured in 1.75 liters more. Now there are 2.55 liters.
  2. Undo the adding: 2.55 − 1.75 = 0.80.
  3. She had 0.80 liters to start.

Words to know

equation
A number sentence with an equals sign.
solve
To find the number that makes it true.

Watch out

Try it

  1. x + 5 = 12. What is x?
  2. 4x = 20. What is x?
  3. x − 3 = 10. What is x?
  4. x ÷ 2 = 6. What is x?
Answers: 1. 7 · 2. 5 · 3. 13 · 4. 12
For grown-upsHide a number under a cup and give a clue like 'plus 5 makes 12'.
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