Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 135 · 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 the smallest whole number by which 256 must be divided to get a perfect cube?
2. 2.What is ∛8000? =
3. 3.Which of these is a perfect cube? (a) 64 (b) 98 (c) 102
4. 4.What is ∛4096? =
5. 5.A cube has a volume of 6859 cubic cm. How long is each edge (in cm)?
6. 6.What is 15³? =
7. 7.What is 9³? =
8. 8.Which of these is a perfect cube? (a) 3596 (b) 3375 (c) 3872
9. 9.A big cube of edge 18 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
10. 10.What is ∛9261? =
11. 11.A big cube of edge 6 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
12. 12.Which of these is a perfect cube? (a) 269 (b) 293 (c) 216
13. 13.What is 6³? =
14. 14.What is ∛343? =
15. 15.What is 20³? =
16. 16.What is ∛5832? =
17. 17.What is the smallest whole number by which 32 must be multiplied to get a perfect cube?
18. 18.What is the smallest whole number by which 875 must be multiplied to get a perfect cube?
19. 19.What is the smallest whole number by which 1944 must be divided to get a perfect cube?
20. 20.What is 18³? =
21. 21.What is the smallest whole number by which 32 must be divided to get a perfect cube?
22. 22.What is ∛216? =
23. 23.What is 11³? =
24. 24.What is ∛2744? =
25. 25.A big cube of edge 9 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
26. 26.What is 5³? =
27. 27.What is ∛8? =
28. 28.A big cube of edge 4 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
29. 29.What is ∛64? =
30. 30.What is ∛125? =
31. 31.What is the smallest whole number by which 108 must be multiplied to get a perfect cube?
32. 32.What is the smallest whole number by which 648 must be divided to get a perfect cube?
33. 33.What is the smallest whole number by which 54 must be divided to get a perfect cube?
34. 34.Which of these is a perfect cube? (a) 2817 (b) 2744 (c) 3149
35. 35.A cube has a volume of 8000 cubic cm. How long is each edge (in cm)?
36. 36.What is the smallest whole number by which 1512 must be multiplied to get a perfect cube?
37. 37.A cube has a volume of 125 cubic cm. How long is each edge (in cm)?
38. 38.What is 12³? =
39. 39.A big cube of edge 12 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
40. 40.A cube has a volume of 2197 cubic cm. How long is each edge (in cm)?

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