Unsectioned
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Squaring numbers close to 100
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Last updated
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Date created
Aug 7, 2020
Cards (3)
Unsectioned
(3 cards)
Squaring numbers close to 100
Find the number minus 100, add this to the original number, square the number minus 100, and combine the two.
Ex. 97^2
97 + (97 - 100) = 97 - 3 = 94
(97 - 100)^2 = 3^2 = 09 -> The answer is 9,409.
Square numbers ending in 5
Answer always ends in 25. We multiply the furthest left digit with one greater and put the numbers together:
Ex. 25^2
2 * 3 = 6 -> Add 25 at the end to get the answer, 625.
Squaring numbers in the 50s
Add 25 plus the number in the ones place, square the ones digit, and puts the two numbers together.
Ex. 53^2
25 + 3 = 28
3^2 = 09 -> The answer is 2809.