Let’s solve each problem step by step.
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Problem 1:
*I think of a number, double it and add 4. The answer is 22.*
→ Let the number be x.
→ Double it: 2x
→ Add 4: 2x + 4 = 22
→ Subtract 4 from both sides: 2x = 18
→ Divide by 2: x = 9
✔
Check: 9 × 2 = 18; 18 + 4 = 22 → Correct!
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Problem 2:
*I think of a number, double it and add 10. The answer is 34.*
→ 2x + 10 = 34
→ 2x = 24
→ x = 12
✔
Check: 12 × 2 = 24; 24 + 10 = 34 → Correct!
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Problem 3:
*I think of a number, double it and subtract 3. The answer is 13.*
→ 2x - 3 = 13
→ 2x = 16
→ x = 8
✔
Check: 8 × 2 = 16; 16 - 3 = 13 → Correct!
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Problem 4:
*I think of a number, double it and subtract 6. The answer is 24.*
→ 2x - 6 = 24
→ 2x = 30
→ x = 15
✔
Check: 15 × 2 = 30; 30 - 6 = 24 → Correct!
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Problem 5:
*I think of a number, halve it and add 4. The answer is 14.*
→ (x ÷ 2) + 4 = 14
→ x ÷ 2 = 10
→ x = 20
✔
Check: 20 ÷ 2 = 10; 10 + 4 = 14 → Correct!
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Problem 6:
*I think of a number, halve it and add 7. The answer is 17.*
→ (x ÷ 2) + 7 = 17
→ x ÷ 2 = 10
→ x = 20
✔
Check: 20 ÷ 2 = 10; 10 + 7 = 17 → Correct!
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Problem 7:
*I think of a number, halve it and subtract 1. The answer is 5.*
→ (x ÷ 2) - 1 = 5
→ x ÷ 2 = 6
→ x = 12
✔
Check: 12 ÷ 2 = 6; 6 - 1 = 5 → Correct!
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Problem 8:
*I think of a number, halve it and subtract 3. The answer is 47.*
→ (x ÷ 2) - 3 = 47
→ x ÷ 2 = 50
→ x = 100
✔
Check: 100 ÷ 2 = 50; 50 - 3 = 47 → Correct!
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Final Answer:
1. 9
2. 12
3. 8
4. 15
5. 20
6. 20
7. 12
8. 100
Parent Tip: Review the logic above to help your child master the concept of printable maths worksheets ks2 problem solving.
