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juliaroberts juliaroberts
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Posts: 157
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11 years ago
There is a trick solving double digit exponents (ex. 52^2) and something with the number 50. Does anyone know? If so, how do you solve all other double digits under 30, or above 70?
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wrote...
11 years ago
The only trick I know is an accelerator:

(a + b) = a^2 + 2 * a * b + b^2

for a=50
the term   2 * a * b  will always be 100 * b.

Try with 57
2500
+700 since 100 * b = 700
+49
total 3249

The recipe is:
-- square the first digit
-- add the second digit
-- append 2 zero
-- add the square of the second digit.

try with 59 (the worst case)
25
34
3400
3481

 try with 53
25
28
2800
2809
wrote...
11 years ago
what do you want?
59^2 = ? working base 50 = 100/2
59 + 9
59 + 9
---------------
(59 + 9) / 2 and (9)*(9) = 3481 answer

23^2 = ? working base 20 = 10*2
23 + 3
23 + 3
---------------
(23 + 3)*2 and (3)(3) = 529

78^2 = ? working base = 70 = 10*7
78 + 8
78 + 8
--------------
(78 + 8)*7 and (8)(8) = 602 and 64 = 6084
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