Class 8 Maths Worksheet: Cubes and Cube Roots
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.
NameDateTime takenScore ___ / 40
- 1.A cube has a volume of 4096 cubic cm. How long is each edge (in cm)?
- 2.What is 20³? =
- 3.What is ∛8000? =
- 4.What is the smallest whole number by which 3136 must be multiplied to get a perfect cube?
- 5.Which of these is a perfect cube? (a) 2849 (b) 2744 (c) 3152
- 6.What is the smallest whole number by which 875 must be divided to get a perfect cube?
- 7.A big cube of edge 5 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
- 8.What is ∛2197? =
- 9.Which of these is a perfect cube? (a) 100 (b) 111 (c) 64
- 10.What is the smallest whole number by which 108 must be multiplied to get a perfect cube?
- 11.A big cube of edge 18 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
- 12.What is 4³? =
- 13.Which of these is a perfect cube? (a) 1981 (b) 1961 (c) 1728
- 14.What is the smallest whole number by which 1944 must be multiplied to get a perfect cube?
- 15.What is ∛9261? =
- 16.What is 13³? =
- 17.What is the smallest whole number by which 16 must be multiplied to get a perfect cube?
- 18.A cube has a volume of 512 cubic cm. How long is each edge (in cm)?
- 19.A cube has a volume of 1331 cubic cm. How long is each edge (in cm)?
- 20.A cube has a volume of 6859 cubic cm. How long is each edge (in cm)?
- 21.A cube has a volume of 2744 cubic cm. How long is each edge (in cm)?
- 22.A big cube of edge 9 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
- 23.A big cube of edge 3 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
- 24.A big cube of edge 20 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
- 25.What is ∛4096? =
- 26.What is the smallest whole number by which 448 must be multiplied to get a perfect cube?
- 27.A big cube of edge 2 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
- 28.What is 19³? =
- 29.What is ∛1000? =
- 30.What is the smallest whole number by which 625 must be divided to get a perfect cube?
- 31.What is 5³? =
- 32.What is 6³? =
- 33.What is ∛5832? =
- 34.What is ∛10648? =
- 35.What is 2³? =
- 36.What is ∛4913? =
- 37.What is 12³? =
- 38.What is 11³? =
- 39.A big cube of edge 6 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
- 40.What is ∛27? =
Answer key
- 16
- 8000
- 20
- 7
- 2744
- 7
- 125
- 13
- 64
- 2
- 216
- 64
- 1728
- 3
- 21
- 2197
- 4
- 8
- 11
- 19
- 14
- 27
- 27
- 125
- 16
- 49
- 8
- 6859
- 10
- 5
- 125
- 216
- 18
- 22
- 8
- 17
- 1728
- 1331
- 8
- 3
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