Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 235 · 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 14³? =
2. 2.A big cube of edge 18 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
3. 3.What is ∛3375? =
4. 4.Which of these is a perfect cube? (a) 1728 (b) 1891 (c) 2038
5. 5.What is the smallest whole number by which 875 must be divided to get a perfect cube?
6. 6.Which of these is a perfect cube? (a) 407 (b) 343 (c) 354
7. 7.A big cube of edge 5 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
8. 8.What is ∛6859? =
9. 9.What is 13³? =
10. 10.A cube has a volume of 216 cubic cm. How long is each edge (in cm)?
11. 11.What is 17³? =
12. 12.What is 9³? =
13. 13.Which of these is a perfect cube? (a) 1331 (b) 1429 (c) 1549
14. 14.What is the smallest whole number by which 10584 must be multiplied to get a perfect cube?
15. 15.A cube has a volume of 1000 cubic cm. How long is each edge (in cm)?
16. 16.What is the smallest whole number by which 648 must be divided to get a perfect cube?
17. 17.A big cube of edge 3 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
18. 18.What is ∛729? =
19. 19.What is 15³? =
20. 20.Which of these is a perfect cube? (a) 136 (b) 150 (c) 125
21. 21.What is the smallest whole number by which 189 must be multiplied to get a perfect cube?
22. 22.A big cube of edge 12 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
23. 23.What is the smallest whole number by which 3 must be divided to get a perfect cube?
24. 24.Which of these is a perfect cube? (a) 958 (b) 729 (c) 765
25. 25.A cube has a volume of 2744 cubic cm. How long is each edge (in cm)?
26. 26.What is 16³? =
27. 27.What is 8³? =
28. 28.What is ∛125? =
29. 29.Which of these is a perfect cube? (a) 1189 (b) 1000 (c) 1221
30. 30.A big cube of edge 2 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
31. 31.What is 6³? =
32. 32.What is 18³? =
33. 33.What is 10³? =
34. 34.What is ∛4096? =
35. 35.What is 5³? =
36. 36.What is 7³? =
37. 37.A big cube of edge 6 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
38. 38.Which of these is a perfect cube? (a) 2295 (b) 2545 (c) 2197
39. 39.What is the smallest whole number by which 3136 must be divided to get a perfect cube?
40. 40.What is the smallest whole number by which 200 must be multiplied to get a perfect cube?

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