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.How many whole numbers lie between 48² and 49²?
- 2.What is 15²? =
- 3.What is the smallest whole number by which 98 must be divided to get a perfect square?
- 4.What is 69²? =
- 5.What is the sum of the first 30 odd numbers (1 + 3 + 5 + …)?
- 6.How many whole numbers lie between 35² and 36²?
- 7.What is 91²? =
- 8.What is 83²? =
- 9.What is √441? =
- 10.What is the sum of the first 21 odd numbers (1 + 3 + 5 + …)?
- 11.What is √9409? =
- 12.A square garden has an area of 529 square m. How long is each side (in m)?
- 13.What is the sum of the first 20 odd numbers (1 + 3 + 5 + …)?
- 14.What is √9025? =
- 15.What is the smallest whole number by which 176 must be divided to get a perfect square?
- 16.What is the sum of the first 15 odd numbers (1 + 3 + 5 + …)?
- 17.What is the sum of the first 17 odd numbers (1 + 3 + 5 + …)?
- 18.How many whole numbers lie between 18² and 19²?
- 19.What is the sum of the first 5 odd numbers (1 + 3 + 5 + …)?
- 20.A square garden has an area of 121 square m. How long is each side (in m)?
- 21.What is √3364? =
- 22.What is the sum of the first 9 odd numbers (1 + 3 + 5 + …)?
- 23.What is 64²? =
- 24.What is √1296? =
- 25.What is the sum of the first 8 odd numbers (1 + 3 + 5 + …)?
- 26.A square garden has an area of 81 square m. How long is each side (in m)?
- 27.What is the smallest whole number by which 12 must be multiplied to get a perfect square?
- 28.What is √1024? =
- 29.What is the smallest whole number by which 50 must be multiplied to get a perfect square?
- 30.What is 17²? =
- 31.What is √2809? =
- 32.How many whole numbers lie between 31² and 32²?
- 33.What is √2500? =
- 34.Which of these is a perfect square? (a) 332 (b) 341 (c) 324
- 35.How many whole numbers lie between 29² and 30²?
- 36.What is 40²? =
- 37.What is the sum of the first 11 odd numbers (1 + 3 + 5 + …)?
- 38.How many whole numbers lie between 19² and 20²?
- 39.What is the smallest whole number by which 48 must be divided to get a perfect square?
- 40.How many whole numbers lie between 9² and 10²?
Answer key
- 96
- 225
- 2
- 4761
- 900
- 70
- 8281
- 6889
- 21
- 441
- 97
- 23
- 400
- 95
- 11
- 225
- 289
- 36
- 25
- 11
- 58
- 81
- 4096
- 36
- 64
- 9
- 3
- 32
- 2
- 289
- 53
- 62
- 50
- 324
- 58
- 1600
- 121
- 38
- 3
- 18
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