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.What is the smallest whole number by which 7 must be multiplied to get a perfect cube?
- 2.What is ∛13824? =
- 3.What is ∛1331? =
- 4.What is the smallest whole number by which 500 must be divided to get a perfect cube?
- 5.A cube has a volume of 4096 cubic cm. How long is each edge (in cm)?
- 6.What is the smallest whole number by which 1512 must be multiplied to get a perfect cube?
- 7.What is 8³? =
- 8.Which of these is a perfect cube? (a) 3477 (b) 3375 (c) 3904
- 9.What is the smallest whole number by which 108 must be multiplied to get a perfect cube?
- 10.A cube has a volume of 3375 cubic cm. How long is each edge (in cm)?
- 11.A big cube of edge 2 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
- 12.What is 9³? =
- 13.A cube has a volume of 125 cubic cm. How long is each edge (in cm)?
- 14.What is ∛343? =
- 15.A big cube of edge 3 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
- 16.What is ∛2744? =
- 17.A big cube of edge 24 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
- 18.What is the smallest whole number by which 49 must be multiplied to get a perfect cube?
- 19.What is 7³? =
- 20.A big cube of edge 16 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
- 21.What is ∛729? =
- 22.What is the smallest whole number by which 864 must be multiplied to get a perfect cube?
- 23.Which of these is a perfect cube? (a) 729 (b) 950 (c) 957
- 24.What is ∛3375? =
- 25.What is ∛216? =
- 26.Which of these is a perfect cube? (a) 36 (b) 30 (c) 27
- 27.A big cube of edge 20 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
- 28.A cube has a volume of 729 cubic cm. How long is each edge (in cm)?
- 29.A big cube of edge 6 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
- 30.What is 3³? =
- 31.Which of these is a perfect cube? (a) 2594 (b) 2409 (c) 2197
- 32.A big cube of edge 12 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
- 33.What is the smallest whole number by which 54 must be multiplied to get a perfect cube?
- 34.What is 2³? =
- 35.A big cube of edge 10 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
- 36.What is ∛512? =
- 37.What is ∛4096? =
- 38.A big cube of edge 6 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
- 39.What is ∛8? =
- 40.What is the smallest whole number by which 3 must be multiplied to get a perfect cube?
Answer key
- 49
- 24
- 11
- 4
- 16
- 49
- 512
- 3375
- 2
- 15
- 8
- 729
- 5
- 7
- 27
- 14
- 216
- 7
- 343
- 64
- 9
- 2
- 729
- 15
- 6
- 27
- 125
- 9
- 8
- 27
- 2197
- 27
- 4
- 8
- 125
- 8
- 16
- 216
- 2
- 9
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