Class 8 Maths Worksheet: Squares and Square Roots
The method (Pairs make squares): Square: n × n. Quick way: (a + b)² = a² + 2ab + b², e.g. 42² = 1600 + 160 + 4. Square root: the number that times itself gives the square; a square ending in 4 has a root ending in 2 or 8. Make a perfect square: break into primes; multiply (or divide) by the prime left without a partner. 1 + 3 + 5 + … (n odd numbers) = n². Between n² and (n + 1)² there are 2n whole numbers.
NameDateTime takenScore ___ / 40
- 1.Which of these is a perfect square? (a) 643 (b) 625 (c) 634
- 2.What is the smallest whole number by which 640 must be multiplied to get a perfect square?
- 3.What is the smallest whole number by which 810 must be multiplied to get a perfect square?
- 4.What is 92²? =
- 5.What is √729? =
- 6.A square garden has an area of 1681 square m. How long is each side (in m)?
- 7.How many whole numbers lie between 12² and 13²?
- 8.What is 74²? =
- 9.What is the smallest whole number by which 90 must be multiplied to get a perfect square?
- 10.What is √144? =
- 11.What is 47²? =
- 12.Which of these is a perfect square? (a) 864 (b) 841 (c) 888
- 13.What is √484? =
- 14.Which of these is a perfect square? (a) 364 (b) 361 (c) 370
- 15.A square garden has an area of 2116 square m. How long is each side (in m)?
- 16.What is √6561? =
- 17.What is √8100? =
- 18.What is the sum of the first 13 odd numbers (1 + 3 + 5 + …)?
- 19.What is √7056? =
- 20.How many whole numbers lie between 9² and 10²?
- 21.How many whole numbers lie between 5² and 6²?
- 22.What is 12²? =
- 23.What is the sum of the first 24 odd numbers (1 + 3 + 5 + …)?
- 24.What is the smallest whole number by which 240 must be divided to get a perfect square?
- 25.What is 27²? =
- 26.How many whole numbers lie between 17² and 18²?
- 27.What is 43²? =
- 28.What is the sum of the first 6 odd numbers (1 + 3 + 5 + …)?
- 29.Which of these is a perfect square? (a) 620 (b) 623 (c) 576
- 30.What is the sum of the first 28 odd numbers (1 + 3 + 5 + …)?
- 31.What is 97²? =
- 32.How many whole numbers lie between 30² and 31²?
- 33.What is the smallest whole number by which 539 must be multiplied to get a perfect square?
- 34.What is √4761? =
- 35.How many whole numbers lie between 39² and 40²?
- 36.What is the sum of the first 15 odd numbers (1 + 3 + 5 + …)?
- 37.What is 46²? =
- 38.What is 85²? =
- 39.What is √8281? =
- 40.What is the sum of the first 29 odd numbers (1 + 3 + 5 + …)?
Answer key
- 625
- 10
- 10
- 8464
- 27
- 41
- 24
- 5476
- 10
- 12
- 2209
- 841
- 22
- 361
- 46
- 81
- 90
- 169
- 84
- 18
- 10
- 144
- 576
- 15
- 729
- 34
- 1849
- 36
- 576
- 784
- 9409
- 60
- 11
- 69
- 78
- 225
- 2116
- 7225
- 91
- 841
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