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 15²? =
- 2.How many whole numbers lie between 49² and 50²?
- 3.What is √2401? =
- 4.What is 67²? =
- 5.What is the sum of the first 9 odd numbers (1 + 3 + 5 + …)?
- 6.What is the smallest whole number by which 54 must be divided to get a perfect square?
- 7.What is the sum of the first 19 odd numbers (1 + 3 + 5 + …)?
- 8.Which of these is a perfect square? (a) 888 (b) 841 (c) 856
- 9.Which of these is a perfect square? (a) 400 (b) 416 (c) 432
- 10.A square garden has an area of 529 square m. How long is each side (in m)?
- 11.What is 61²? =
- 12.What is the smallest whole number by which 686 must be multiplied to get a perfect square?
- 13.What is the sum of the first 29 odd numbers (1 + 3 + 5 + …)?
- 14.What is √5184? =
- 15.What is √1521? =
- 16.What is the sum of the first 11 odd numbers (1 + 3 + 5 + …)?
- 17.What is 22²? =
- 18.What is √9801? =
- 19.What is 75²? =
- 20.What is the sum of the first 18 odd numbers (1 + 3 + 5 + …)?
- 21.What is the smallest whole number by which 44 must be divided to get a perfect square?
- 22.What is 86²? =
- 23.What is the smallest whole number by which 108 must be multiplied to get a perfect square?
- 24.How many whole numbers lie between 9² and 10²?
- 25.What is 25²? =
- 26.What is the sum of the first 22 odd numbers (1 + 3 + 5 + …)?
- 27.A square garden has an area of 1156 square m. How long is each side (in m)?
- 28.What is 26²? =
- 29.Which of these is a perfect square? (a) 1629 (b) 1600 (c) 1613
- 30.A square garden has an area of 1521 square m. How long is each side (in m)?
- 31.What is the smallest whole number by which 45 must be multiplied to get a perfect square?
- 32.Which of these is a perfect square? (a) 690 (b) 676 (c) 723
- 33.What is √3721? =
- 34.What is the sum of the first 27 odd numbers (1 + 3 + 5 + …)?
- 35.A square garden has an area of 64 square m. How long is each side (in m)?
- 36.Which of these is a perfect square? (a) 472 (b) 453 (c) 441
- 37.What is the smallest whole number by which 20 must be divided to get a perfect square?
- 38.What is √1681? =
- 39.What is the smallest whole number by which 52 must be multiplied to get a perfect square?
- 40.What is the smallest whole number by which 343 must be multiplied to get a perfect square?
Answer key
- 225
- 98
- 49
- 4489
- 81
- 6
- 361
- 841
- 400
- 23
- 3721
- 14
- 841
- 72
- 39
- 121
- 484
- 99
- 5625
- 324
- 11
- 7396
- 3
- 18
- 625
- 484
- 34
- 676
- 1600
- 39
- 5
- 676
- 61
- 729
- 8
- 441
- 5
- 41
- 13
- 7
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