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 12 odd numbers (1 + 3 + 5 + …)?
- 2.What is 96²? =
- 3.What is the smallest whole number by which 360 must be divided to get a perfect square?
- 4.What is the smallest whole number by which 540 must be multiplied to get a perfect square?
- 5.What is the sum of the first 11 odd numbers (1 + 3 + 5 + …)?
- 6.What is √144? =
- 7.What is √1296? =
- 8.What is the smallest whole number by which 350 must be multiplied to get a perfect square?
- 9.What is the smallest whole number by which 686 must be divided to get a perfect square?
- 10.What is the sum of the first 16 odd numbers (1 + 3 + 5 + …)?
- 11.How many whole numbers lie between 9² and 10²?
- 12.What is the sum of the first 28 odd numbers (1 + 3 + 5 + …)?
- 13.A square garden has an area of 169 square m. How long is each side (in m)?
- 14.What is √6561? =
- 15.What is the sum of the first 15 odd numbers (1 + 3 + 5 + …)?
- 16.What is 70²? =
- 17.How many whole numbers lie between 31² and 32²?
- 18.How many whole numbers lie between 39² and 40²?
- 19.What is the smallest whole number by which 56 must be divided to get a perfect square?
- 20.How many whole numbers lie between 43² and 44²?
- 21.What is √1089? =
- 22.What is the sum of the first 30 odd numbers (1 + 3 + 5 + …)?
- 23.Which of these is a perfect square? (a) 1629 (b) 1600 (c) 1636
- 24.How many whole numbers lie between 20² and 21²?
- 25.What is 34²? =
- 26.How many whole numbers lie between 10² and 11²?
- 27.What is 97²? =
- 28.A square garden has an area of 1225 square m. How long is each side (in m)?
- 29.What is √9216? =
- 30.What is 62²? =
- 31.A square garden has an area of 361 square m. How long is each side (in m)?
- 32.What is 48²? =
- 33.What is the smallest whole number by which 98 must be multiplied to get a perfect square?
- 34.What is 92²? =
- 35.A square garden has an area of 121 square m. How long is each side (in m)?
- 36.What is √7744? =
- 37.A square garden has an area of 2704 square m. How long is each side (in m)?
- 38.What is the sum of the first 21 odd numbers (1 + 3 + 5 + …)?
- 39.A square garden has an area of 1600 square m. How long is each side (in m)?
- 40.What is √2809? =
Answer key
- 144
- 9216
- 10
- 15
- 121
- 12
- 36
- 14
- 14
- 256
- 18
- 784
- 13
- 81
- 225
- 4900
- 62
- 78
- 14
- 86
- 33
- 900
- 1600
- 40
- 1156
- 20
- 9409
- 35
- 96
- 3844
- 19
- 2304
- 2
- 8464
- 11
- 88
- 52
- 441
- 40
- 53
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