Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 792 · 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 72 must be divided to get a perfect cube?
2. 2.What is 20³? =
3. 3.A big cube of edge 6 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
4. 4.What is the smallest whole number by which 675 must be multiplied to get a perfect cube?
5. 5.A cube has a volume of 3375 cubic cm. How long is each edge (in cm)?
6. 6.Which of these is a perfect cube? (a) 729 (b) 859 (c) 830
7. 7.Which of these is a perfect cube? (a) 1173 (b) 1000 (c) 1285
8. 8.What is 13³? =
9. 9.A big cube of edge 20 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
10. 10.What is 2³? =
11. 11.What is ∛216? =
12. 12.What is 8³? =
13. 13.What is 4³? =
14. 14.What is the smallest whole number by which 3 must be divided to get a perfect cube?
15. 15.Which of these is a perfect cube? (a) 189 (b) 125 (c) 150
16. 16.What is the smallest whole number by which 6125 must be divided to get a perfect cube?
17. 17.A big cube of edge 12 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
18. 18.What is ∛64? =
19. 19.What is the smallest whole number by which 243 must be divided to get a perfect cube?
20. 20.What is ∛9261? =
21. 21.What is ∛1331? =
22. 22.What is the smallest whole number by which 4 must be multiplied to get a perfect cube?
23. 23.Which of these is a perfect cube? (a) 64 (b) 93 (c) 108
24. 24.A big cube of edge 6 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
25. 25.What is 15³? =
26. 26.A cube has a volume of 1728 cubic cm. How long is each edge (in cm)?
27. 27.A cube has a volume of 343 cubic cm. How long is each edge (in cm)?
28. 28.What is 11³? =
29. 29.Which of these is a perfect cube? (a) 322 (b) 216 (c) 232
30. 30.What is ∛8? =
31. 31.A cube has a volume of 729 cubic cm. How long is each edge (in cm)?
32. 32.What is 18³? =
33. 33.A cube has a volume of 2197 cubic cm. How long is each edge (in cm)?
34. 34.Which of these is a perfect cube? (a) 2437 (b) 2197 (c) 2645
35. 35.What is 5³? =
36. 36.What is ∛512? =
37. 37.A big cube of edge 6 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
38. 38.What is ∛5832? =
39. 39.What is 12³? =
40. 40.A big cube of edge 10 cm is cut into small cubes of edge 2 cm. How many small cubes are there?

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