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 sum of the first 18 odd numbers (1 + 3 + 5 + …)?
- 2.What is the smallest whole number by which 540 must be divided to get a perfect square?
- 3.What is √1296? =
- 4.How many whole numbers lie between 5² and 6²?
- 5.What is √625? =
- 6.What is the sum of the first 23 odd numbers (1 + 3 + 5 + …)?
- 7.What is the sum of the first 17 odd numbers (1 + 3 + 5 + …)?
- 8.What is the sum of the first 28 odd numbers (1 + 3 + 5 + …)?
- 9.How many whole numbers lie between 44² and 45²?
- 10.What is the sum of the first 6 odd numbers (1 + 3 + 5 + …)?
- 11.What is 15²? =
- 12.What is √8649? =
- 13.What is 74²? =
- 14.What is 17²? =
- 15.What is 79²? =
- 16.What is the smallest whole number by which 1134 must be divided to get a perfect square?
- 17.What is 60²? =
- 18.A square garden has an area of 225 square m. How long is each side (in m)?
- 19.What is 64²? =
- 20.What is 34²? =
- 21.What is the sum of the first 5 odd numbers (1 + 3 + 5 + …)?
- 22.What is the smallest whole number by which 125 must be multiplied to get a perfect square?
- 23.What is √6084? =
- 24.How many whole numbers lie between 30² and 31²?
- 25.What is 25²? =
- 26.A square garden has an area of 196 square m. How long is each side (in m)?
- 27.How many whole numbers lie between 35² and 36²?
- 28.What is √484? =
- 29.Which of these is a perfect square? (a) 841 (b) 860 (c) 869
- 30.How many whole numbers lie between 31² and 32²?
- 31.What is √3969? =
- 32.What is √6241? =
- 33.What is √4225? =
- 34.What is √256? =
- 35.What is the smallest whole number by which 162 must be multiplied to get a perfect square?
- 36.What is the sum of the first 7 odd numbers (1 + 3 + 5 + …)?
- 37.A square garden has an area of 2209 square m. How long is each side (in m)?
- 38.What is 21²? =
- 39.What is the smallest whole number by which 75 must be multiplied to get a perfect square?
- 40.What is the sum of the first 12 odd numbers (1 + 3 + 5 + …)?
Answer key
- 324
- 15
- 36
- 10
- 25
- 529
- 289
- 784
- 88
- 36
- 225
- 93
- 5476
- 289
- 6241
- 14
- 3600
- 15
- 4096
- 1156
- 25
- 5
- 78
- 60
- 625
- 14
- 70
- 22
- 841
- 62
- 63
- 79
- 65
- 16
- 2
- 49
- 47
- 441
- 3
- 144
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