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 21 odd numbers (1 + 3 + 5 + …)?
- 2.What is the smallest whole number by which 960 must be multiplied to get a perfect square?
- 3.What is √729? =
- 4.What is the sum of the first 10 odd numbers (1 + 3 + 5 + …)?
- 5.How many whole numbers lie between 37² and 38²?
- 6.What is 24²? =
- 7.Which of these is a perfect square? (a) 676 (b) 688 (c) 691
- 8.What is √6724? =
- 9.What is 60²? =
- 10.How many whole numbers lie between 15² and 16²?
- 11.What is 87²? =
- 12.A square garden has an area of 1764 square m. How long is each side (in m)?
- 13.A square garden has an area of 225 square m. How long is each side (in m)?
- 14.What is the sum of the first 27 odd numbers (1 + 3 + 5 + …)?
- 15.What is 99²? =
- 16.What is 68²? =
- 17.What is √8836? =
- 18.What is 22²? =
- 19.What is √3249? =
- 20.How many whole numbers lie between 16² and 17²?
- 21.What is 74²? =
- 22.A square garden has an area of 1444 square m. How long is each side (in m)?
- 23.Which of these is a perfect square? (a) 1590 (b) 1521 (c) 1538
- 24.Which of these is a perfect square? (a) 127 (b) 132 (c) 121
- 25.A square garden has an area of 2916 square m. How long is each side (in m)?
- 26.What is √5041? =
- 27.What is the smallest whole number by which 735 must be divided to get a perfect square?
- 28.What is the smallest whole number by which 128 must be multiplied to get a perfect square?
- 29.What is 18²? =
- 30.What is √2401? =
- 31.Which of these is a perfect square? (a) 225 (b) 231 (c) 249
- 32.How many whole numbers lie between 34² and 35²?
- 33.What is √2209? =
- 34.What is √361? =
- 35.What is 80²? =
- 36.What is √676? =
- 37.How many whole numbers lie between 46² and 47²?
- 38.What is the sum of the first 18 odd numbers (1 + 3 + 5 + …)?
- 39.What is √4624? =
- 40.What is the sum of the first 20 odd numbers (1 + 3 + 5 + …)?
Answer key
- 441
- 15
- 27
- 100
- 74
- 576
- 676
- 82
- 3600
- 30
- 7569
- 42
- 15
- 729
- 9801
- 4624
- 94
- 484
- 57
- 32
- 5476
- 38
- 1521
- 121
- 54
- 71
- 15
- 2
- 324
- 49
- 225
- 68
- 47
- 19
- 6400
- 26
- 92
- 324
- 68
- 400
Free maths worksheets lessons, practice and worksheets at talentjr.in/maths-worksheets