Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 853 · 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 4³? =
2. 2.What is the smallest whole number by which 10584 must be divided to get a perfect cube?
3. 3.Which of these is a perfect cube? (a) 1576 (b) 1350 (c) 1331
4. 4.What is 18³? =
5. 5.What is ∛8000? =
6. 6.A cube has a volume of 2744 cubic cm. How long is each edge (in cm)?
7. 7.What is ∛13824? =
8. 8.A cube has a volume of 2197 cubic cm. How long is each edge (in cm)?
9. 9.What is 8³? =
10. 10.What is ∛27? =
11. 11.What is 7³? =
12. 12.What is the smallest whole number by which 128 must be multiplied to get a perfect cube?
13. 13.What is the smallest whole number by which 192 must be divided to get a perfect cube?
14. 14.What is 13³? =
15. 15.A big cube of edge 4 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
16. 16.What is the smallest whole number by which 576 must be divided to get a perfect cube?
17. 17.What is 12³? =
18. 18.A big cube of edge 5 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
19. 19.What is 6³? =
20. 20.Which of these is a perfect cube? (a) 64 (b) 105 (c) 76
21. 21.Which of these is a perfect cube? (a) 198 (b) 141 (c) 125
22. 22.Which of these is a perfect cube? (a) 2376 (b) 2197 (c) 2426
23. 23.Which of these is a perfect cube? (a) 216 (b) 221 (c) 283
24. 24.What is the smallest whole number by which 1944 must be divided to get a perfect cube?
25. 25.A big cube of edge 6 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
26. 26.What is 16³? =
27. 27.What is 3³? =
28. 28.A big cube of edge 20 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
29. 29.What is the smallest whole number by which 5 must be divided to get a perfect cube?
30. 30.What is 5³? =
31. 31.Which of these is a perfect cube? (a) 769 (b) 729 (c) 964
32. 32.A cube has a volume of 64 cubic cm. How long is each edge (in cm)?
33. 33.What is the smallest whole number by which 24 must be multiplied to get a perfect cube?
34. 34.What is the smallest whole number by which 135 must be multiplied to get a perfect cube?
35. 35.A big cube of edge 18 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
36. 36.What is 15³? =
37. 37.What is 19³? =
38. 38.What is the smallest whole number by which 2 must be multiplied to get a perfect cube?
39. 39.What is the smallest whole number by which 250 must be divided to get a perfect cube?
40. 40.A cube has a volume of 343 cubic cm. How long is each edge (in cm)?

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