Work through the levels in order. Type your answer and press Check — open the worked solution if you get stuck. Answers like -6, 3/4 or 0.25 are typed exactly as shown. A ⭐ Bonus Challenge at the end is extra credit — skip it if the rest was hard work.
Level 1 · Warm-up
1 What number goes in the box?
Show worked solution
14 − 6 = 8. Check: 6 + 8 = 14. ✓
2 Write the number that goes in the box in each of these two sentences.
Show worked solution
First: 21 − 9 = 12. Second: 21 + 9 = 30. The same two numbers give different answers depending on where the box sits.
3 What number goes in the box in ? − 9 = 20?
Show worked solution
20 + 9 = 29. Check: 29 − 9 = 20. ✓
Level 2 · Core
4 What number goes in the box?
Show worked solution
30 − 18 = 12. Check: 30 − 12 = 18. ✓
5 Write the number that goes in the box in each of these two sentences.
Show worked solution
42 ÷ 7 = 6 and 63 ÷ 7 = 9. Check: 7 × 6 = 42 and 7 × 9 = 63. ✓
6 What number goes in the box in ? ÷ 4 = 3?
Show worked solution
3 × 4 = 12. Check: 12 ÷ 4 = 3. ✓
Level 3 · Challenge
7 Look at this number sentence.1 The box is 9.
2 The box is 41.
3 Working out 25 − 16 finds the box.
Which statements are correct?
2 The box is 41.
3 Working out 25 − 16 finds the box.
Which statements are correct?
Show worked solution
25 − 16 = 9, so the box is 9 (1 ✓, 3 ✓) and not 41 (2 ✗ — that is bigger than the whole). 1 and 3.
8 A class had some pencils, gave 14 away and has 27 left. Write the number the class started with, and the number left if it gave 20 away instead.
Show worked solution
It started with 27 + 14 = 41, so giving 20 away leaves 41 − 20 = 21.
9 What number goes in the box in 6 × ? = 30?
Show worked solution
30 ÷ 6 = 5. Check: 6 × 5 = 30. ✓