Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 895 · 40 sums

The method (Threes make cubes): Cube: n × n × n. Cube root: the number that, used three times, gives the cube. Units digits: 1→1, 2→8, 3→7, 4→4, 5→5, 6→6, 7→3, 8→2, 9→9, 0→0 — use them to guess cube roots. Make a perfect cube: break into primes; multiply by what completes each group of three (or divide by what is left over). A big cube of edge a cut into small cubes of edge b gives (a ÷ b)³ small cubes.

1. 1.What is 17³? =
2. 2.What is 20³? =
3. 3.What is the smallest whole number by which 40 must be multiplied to get a perfect cube?
4. 4.Which of these is a perfect cube? (a) 35 (b) 27 (c) 30
5. 5.What is ∛13824? =
6. 6.What is ∛216? =
7. 7.What is ∛1728? =
8. 8.What is the smallest whole number by which 192 must be multiplied to get a perfect cube?
9. 9.Which of these is a perfect cube? (a) 1376 (b) 1331 (c) 1450
10. 10.What is 9³? =
11. 11.A cube has a volume of 125 cubic cm. How long is each edge (in cm)?
12. 12.A big cube of edge 6 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
13. 13.What is 11³? =
14. 14.What is 6³? =
15. 15.What is ∛15625? =
16. 16.A big cube of edge 6 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
17. 17.A cube has a volume of 27 cubic cm. How long is each edge (in cm)?
18. 18.A cube has a volume of 216 cubic cm. How long is each edge (in cm)?
19. 19.A cube has a volume of 2744 cubic cm. How long is each edge (in cm)?
20. 20.Which of these is a perfect cube? (a) 2155 (b) 1728 (c) 1886
21. 21.A cube has a volume of 1728 cubic cm. How long is each edge (in cm)?
22. 22.What is 4³? =
23. 23.What is ∛64? =
24. 24.A cube has a volume of 8 cubic cm. How long is each edge (in cm)?
25. 25.What is 18³? =
26. 26.What is 5³? =
27. 27.A big cube of edge 24 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
28. 28.A big cube of edge 8 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
29. 29.Which of these is a perfect cube? (a) 2744 (b) 2944 (c) 3284
30. 30.Which of these is a perfect cube? (a) 3375 (b) 3609 (c) 3766
31. 31.What is ∛6859? =
32. 32.What is 7³? =
33. 33.A cube has a volume of 1331 cubic cm. How long is each edge (in cm)?
34. 34.What is the smallest whole number by which 392 must be divided to get a perfect cube?
35. 35.What is the smallest whole number by which 40 must be divided to get a perfect cube?
36. 36.Which of these is a perfect cube? (a) 125 (b) 142 (c) 182
37. 37.What is ∛12167? =
38. 38.A big cube of edge 9 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
39. 39.What is ∛9261? =
40. 40.What is ∛1000? =

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