6 · Two-Step Equations
Solve equations like 3x + 5 = 20 in two steps.
What your child learns
- Undo addition/subtraction first
- Then undo multiplication/division
- Check your answer in the original equation
Example
3x + 5 = 20 → 3x = 15 → x = 5.
Mini lesson: Two-Step Equations
Goal: Solve equations like 3x + 5 = 20 in two steps.
Undo operations in reverse order: first undo adding/subtracting, then undo multiplying/dividing.
Worked example
Solve 3x + 5 = 20.
- Subtract 5 from both sides: 3x = 15
- Divide both sides by 3: x = 5
- Check: 3 × 5 + 5 = 20 ✔
Common mistakes
- Dividing first: (20 ÷ 3) is messy and usually leads to errors.
- Only dividing one term by 3.
Practice questions
A taste of the questions in BloomTracks – the app makes fresh ones every time and adjusts the level as your child answers.
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Question 1 · Level 1
To solve 9x + 3 = 66, what is the best first step?
- Divide both sides by 9
- Add 3 to both sides
- Subtract 9 from both sides
- Subtract 3 from both sides
Show the answer
Answer: Subtract 3 from both sides
Subtract 3 from both sides: 9x = 63. Then divide by 9: x = 7.
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Question 2 · Level 3
Solve: 8n − 9 = 55
Show the answer
Answer: 8
n = 8
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Question 3 · Level 5
Solve: 5x − 16 = −6
Show the answer
Answer: 2
x = 2
Try it at home
Make two-step number puzzles for each other.
Key takeaway
Undo operations in the reverse order they were done.
Practise 6 · two-step equations with Bloomie
Bloomie reads every question aloud, listens to spoken answers and adapts the difficulty one question at a time.