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.What is the smallest whole number by which 20 must be multiplied to get a perfect square?
- 2.What is √1600? =
- 3.What is the sum of the first 28 odd numbers (1 + 3 + 5 + …)?
- 4.Which of these is a perfect square? (a) 216 (b) 196 (c) 215
- 5.What is √4624? =
- 6.What is 49²? =
- 7.What is the sum of the first 29 odd numbers (1 + 3 + 5 + …)?
- 8.What is √576? =
- 9.A square garden has an area of 100 square m. How long is each side (in m)?
- 10.What is √5041? =
- 11.What is √900? =
- 12.What is 37²? =
- 13.What is √9025? =
- 14.A square garden has an area of 225 square m. How long is each side (in m)?
- 15.How many whole numbers lie between 5² and 6²?
- 16.What is the smallest whole number by which 99 must be divided to get a perfect square?
- 17.How many whole numbers lie between 33² and 34²?
- 18.What is √4225? =
- 19.What is the sum of the first 15 odd numbers (1 + 3 + 5 + …)?
- 20.Which of these is a perfect square? (a) 1434 (b) 1370 (c) 1369
- 21.What is 98²? =
- 22.What is √4356? =
- 23.What is the smallest whole number by which 224 must be divided to get a perfect square?
- 24.What is the smallest whole number by which 147 must be divided to get a perfect square?
- 25.What is √8649? =
- 26.How many whole numbers lie between 14² and 15²?
- 27.A square garden has an area of 81 square m. How long is each side (in m)?
- 28.What is √2116? =
- 29.What is the sum of the first 24 odd numbers (1 + 3 + 5 + …)?
- 30.How many whole numbers lie between 47² and 48²?
- 31.What is the sum of the first 23 odd numbers (1 + 3 + 5 + …)?
- 32.What is 18²? =
- 33.What is √4489? =
- 34.A square garden has an area of 196 square m. How long is each side (in m)?
- 35.How many whole numbers lie between 29² and 30²?
- 36.A square garden has an area of 324 square m. How long is each side (in m)?
- 37.What is the sum of the first 9 odd numbers (1 + 3 + 5 + …)?
- 38.What is the sum of the first 6 odd numbers (1 + 3 + 5 + …)?
- 39.Which of these is a perfect square? (a) 563 (b) 532 (c) 529
- 40.What is 40²? =
Answer key
- 5
- 40
- 784
- 196
- 68
- 2401
- 841
- 24
- 10
- 71
- 30
- 1369
- 95
- 15
- 10
- 11
- 66
- 65
- 225
- 1369
- 9604
- 66
- 14
- 3
- 93
- 28
- 9
- 46
- 576
- 94
- 529
- 324
- 67
- 14
- 58
- 18
- 81
- 36
- 529
- 1600
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