When calculating the decimal addition and subtraction method, Congcong mistook the subtraction 25.7 as 52.7, and the result was equal to 13.6. What should be the correct result?

When calculating the decimal addition and subtraction method, Congcong mistook the subtraction 25.7 as 52.7, and the result was equal to 13.6. What should be the correct result?

Right
52.7-25.7+13.6
=27+13.6
=40.6
If you don't understand this question, you can ask,

(x ^ 2 + y ^ 2) / (x ^ 2-y ^ 2) minus (x + y) / (2x-2y), simplify
My calculation is: x ^ 2-2xy + y ^ 2, which is different from others,

You left out the denominator (x ^ 2 + y ^ 2) / (x ^ 2-y ^ 2) - (x + y) / (2x-2y) = (x ^ 2 + y ^ 2) / (X-Y) (x + y) - (x + y) / 2 (X-Y) = 2 (x ^ 2 + y ^ 2) / 2 (X-Y) (x + y) - (x + y) ^ 2 / 2 (X-Y) (x + y) = [2 (x ^ 2 + y ^ 2) - (x + y) ^ 2] / 2 (X-Y) (x + y) = [2x ^ 2 + 2Y ^ 2 - (x ^ 2 + y ^ 2 + 2XY)] / 2 (x -

First simplify, then calculate. (x ^ 2-9 / x + 2) divided by (x ^ 2-6x + 9 / 2x + 4) minus (2x / x)
First simplify, then numerical
(x ^ 2-9 / x + 2) divided by (x ^ 2-6x + 9 / 2x + 4) minus (2x / x-3), where x equals 1

（x^2-9/x＋2）÷（x^2-6x＋9/2x＋4）-（2x/x-3）
=[(x-3)(x+3)/(x+2)]×[2(x+2)/(x-3)²]-2x/(x-3)
=2(x+3)/(x-3)-2x/(x-3)
=6/(x-3)
=6/(1-3)
=-3