Short cut to find square number
Square of number ending with 5
2 5 × 2 5 ---------- write 5 × 5 = 25 at the end f answer 2(2 + 1) = 6 write 6 before 25 and answer is 625
9 5 × 9 5 --------- write 5 × 5 = 25 at the end f answer 9(9 + 1) = 90 write 90 before 25 and answer is 9025
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Sunil Pradhan
6 years, 7 months ago
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If you know square of any number square of next number or preceding number can be found out.
e.g. 85 ² = 7225 then 86² = 7225 + 85 + 86 = 7396
and 84² = 7225 – (85 + 84) = 7056
There is a trick to find square of any number. Take a number, say 13. Then subtract 3 from it, the no becomes 10. Next add 3 to 13, the no becomes 16. Now multly 10 and 16 and add 9( as it is 3 square) U have the answer 160 +9=169 The trick is to add or subtract a number so that the no becomes a multiple of ten and then add the same no( which was subtracted or added) to the no. To be squared and then multiplyboth and then add the square the no.( the one which was added or subtracted. Hope this helped
There is also another trick to calculate square, which is a bit idiotic way but work sometimes.. Like if you know square of a number, lets say 20 ... = 400. Then square of 21 = sqr(20)+20+21= 441. May it help sometimes.
same way you can have a shortcut to find a square of a number ending with 1. lets say the number is 61. Then...the units digit becomes 1. the tens digit is the digit at units place when 6 is multiplied by 2. that is , 2 (of 12)
and then square the digit at tens place and add the carried over digit(in case of 61..its 1)
therefore the square of 61 becomes....(36+1)21=3721.
Care must be taken while squaring three digit numbers, understanding of the process is necessary for that case.
Square of number ending with 25,
125² = write 25 × 25 = 625 from 125 consider 15 (forget 2 in the middle.) multiply 15 by digit in 100's place. 15 × 1 = 15. at the end of answer write 15 before 625 and answer is 15625
325² = write 25 × 25 = 625 from 325 consider 35 (forget 2 in the middle.) multiply 35 by digit in 100's place. 35 × 3 = 105. write 105 before 625 and answer is 105625
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