Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 460 · 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.A cube has a volume of 27 cubic cm. How long is each edge (in cm)?
2. 2.Which of these is a perfect cube? (a) 94 (b) 64 (c) 107
3. 3.What is the smallest whole number by which 56 must be divided to get a perfect cube?
4. 4.What is the smallest whole number by which 135 must be multiplied to get a perfect cube?
5. 5.What is ∛13824? =
6. 6.What is the smallest whole number by which 448 must be multiplied to get a perfect cube?
7. 7.A cube has a volume of 6859 cubic cm. How long is each edge (in cm)?
8. 8.Which of these is a perfect cube? (a) 239 (b) 216 (c) 278
9. 9.What is 7³? =
10. 10.What is the smallest whole number by which 49 must be divided to get a perfect cube?
11. 11.A big cube of edge 4 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
12. 12.A cube has a volume of 1331 cubic cm. How long is each edge (in cm)?
13. 13.What is ∛27? =
14. 14.A cube has a volume of 1000 cubic cm. How long is each edge (in cm)?
15. 15.Which of these is a perfect cube? (a) 343 (b) 445 (c) 391
16. 16.What is the smallest whole number by which 108 must be multiplied to get a perfect cube?
17. 17.Which of these is a perfect cube? (a) 27 (b) 41 (c) 54
18. 18.A big cube of edge 20 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
19. 19.What is the smallest whole number by which 1080 must be divided to get a perfect cube?
20. 20.What is ∛1331? =
21. 21.What is ∛3375? =
22. 22.What is the smallest whole number by which 250 must be multiplied to get a perfect cube?
23. 23.A big cube of edge 12 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
24. 24.What is ∛512? =
25. 25.What is 6³? =
26. 26.What is the smallest whole number by which 24 must be multiplied to get a perfect cube?
27. 27.What is ∛216? =
28. 28.A big cube of edge 3 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
29. 29.A big cube of edge 4 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
30. 30.What is the smallest whole number by which 3 must be divided to get a perfect cube?
31. 31.A big cube of edge 24 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
32. 32.A cube has a volume of 729 cubic cm. How long is each edge (in cm)?
33. 33.What is the smallest whole number by which 9 must be divided to get a perfect cube?
34. 34.What is the smallest whole number by which 1323 must be divided to get a perfect cube?
35. 35.Which of these is a perfect cube? (a) 801 (b) 861 (c) 729
36. 36.Which of these is a perfect cube? (a) 3662 (b) 3747 (c) 3375
37. 37.Which of these is a perfect cube? (a) 2197 (b) 2646 (c) 2575
38. 38.A big cube of edge 2 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
39. 39.A cube has a volume of 8 cubic cm. How long is each edge (in cm)?
40. 40.A big cube of edge 6 cm is cut into small cubes of edge 1 cm. How many small cubes are there?

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