FIND SQUARE OF NUMBERS IN 200 TO 299
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Steps to find square of numbers in 200's
1. Choose a number in the 200s (start with numbers under 210, then try for larger ones).
2. The first digit of the square is 4: 4 _ _ _ _
3. The next two digits will be 4 times the last 2 digits: _ X X _ _
4. The last two places will be the square of the last digit: _ _ _ X X
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Here we take an Example:
1. let the number be 207:
2. The first digit is 4
so 4 _ _ _ _
3. The next two digits are 4 times the last digit:
4 × 7 = 28
so _ 2 8 _ _
Square the last digit: 7× 7 = 49
so _ _ _ 49
So finally we get 206 × 206 = 42849.
and For larger numbers work right to left:
1. Square the last two digits (keep the carry): _ _ _ X X
2. 4 times the last two digits + carry: _ X X _ _
3. Square the first digit + carry: X _ _ _ _
Example
1. If the number to be squared is 225:
2. Square last two digits (keep carry):
25x25 = 625 (keep 6): _ _ _ 2 5
3. 4 times the last two digits + carry:
4x25 = 100; 100+6 = 106 (keep 1): _ 0 6 _ _
4. Square the first digit + carry:
2x2 = 4; 4+1 = 5: 5 _ _ _ _
5. So 225 × 225 = 50625.
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