Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 312 · 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.Which of these is a perfect cube? (a) 36 (b) 27 (c) 28
2. 2.Which of these is a perfect cube? (a) 3709 (b) 3375 (c) 3938
3. 3.What is 10³? =
4. 4.A big cube of edge 8 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
5. 5.What is ∛512? =
6. 6.What is ∛5832? =
7. 7.What is 16³? =
8. 8.What is ∛1331? =
9. 9.What is ∛3375? =
10. 10.What is ∛1728? =
11. 11.What is 11³? =
12. 12.Which of these is a perfect cube? (a) 1728 (b) 1863 (c) 1858
13. 13.A cube has a volume of 5832 cubic cm. How long is each edge (in cm)?
14. 14.What is 12³? =
15. 15.A cube has a volume of 1728 cubic cm. How long is each edge (in cm)?
16. 16.A big cube of edge 4 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
17. 17.A big cube of edge 12 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
18. 18.A big cube of edge 12 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
19. 19.What is 5³? =
20. 20.What is the smallest whole number by which 243 must be multiplied to get a perfect cube?
21. 21.What is ∛15625? =
22. 22.What is ∛125? =
23. 23.What is the smallest whole number by which 40 must be divided to get a perfect cube?
24. 24.What is 13³? =
25. 25.What is 7³? =
26. 26.What is the smallest whole number by which 49 must be multiplied to get a perfect cube?
27. 27.Which of these is a perfect cube? (a) 79 (b) 96 (c) 64
28. 28.What is ∛216? =
29. 29.What is ∛10648? =
30. 30.What is ∛1000? =
31. 31.Which of these is a perfect cube? (a) 137 (b) 125 (c) 127
32. 32.What is the smallest whole number by which 1323 must be multiplied to get a perfect cube?
33. 33.A cube has a volume of 2197 cubic cm. How long is each edge (in cm)?
34. 34.What is 6³? =
35. 35.A cube has a volume of 8000 cubic cm. How long is each edge (in cm)?
36. 36.A big cube of edge 5 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
37. 37.What is 4³? =
38. 38.A big cube of edge 6 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
39. 39.What is the smallest whole number by which 24 must be divided to get a perfect cube?
40. 40.What is the smallest whole number by which 25 must be multiplied to get a perfect cube?

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