CUBES AND CUBE ROOTS - GRADE 8
MULTIPLE CHOICE QUESTIONS
1. Cube root of an odd number is always an
(a) even number
(b) prime number
(c) odd number
(d) None of these
Ans: c
2. Identify the perfect cube
(a)100 (b) 1000
(c) 10000
(d) 100000
(c) 1.01
(d) 0.11
Ans: b
3. The cube root of 1.331 is
(a) 1.1 (b) 11.1
Ans: a
4. The smallest number by which 81 should be divided to make it a perfect cube is
(a) 3
(b) 6
(c) 9
(d) 18
(c) 42
(d)21
Ans: a
5. The cube root of (-63 × -73) is
(a) 216
(b) -42
Ans: b
GROUP 1
1. What is the unit digit of the cube of 216? (6)
2. Find the least natural number by which 2160 should be divided so that the quotient is a
perfect cube. Also find the cube root of the quotient. (10, 6)
3. Cubes of (a) 729 and (b) 343 will be even or odd? (odd, odd)
4. Check whether 432 is a perfect cube.(no)
5. Find the cube root of 216 × 729. (54)
GROUP 2
1.
2.
3.
4.
Find the cube root of 0.004913 (0.17)
The volume of a cube is 9261000m3. Find the side of the cube. (210m)
If 11x3 = 8019, find x. (9)
Find the sum of the cubes of the first five natural numbers. Obtain the square root of
the sum. (225, 15)
5. Evaluate
[(152 + 82)1/2] 3 (4913)
GROUP 3
1. What is the cube root of the product of two negative integers?
2. Is 392 a perfect cube? If not, find the smallest natural number by which 392 must be
multiplied so that the product is a perfect cube. (no, 7)
3. Three numbers are in the ratio 2:3:4. . The sum of their cubes is 33957. Find the
numbers. (14,21,28)
1
3
4. Find the cube of (5 - 2 ). (512/27)
5. Find the volume of a cube, one face of which has an area 64m2. (512m3)