I have this exercise:
When performing the best approximation by excess to the hundredth of the number $-5,2672$ the error that is committed is
The error must be the absolute value of the substraction between the original number and the approximate number, that is:
$| -5.2672 - r|$, where $r$ is the approximate value, and is $-5.27$. That is a approximation by default, since the approximate value is less than the original.
So, the error must be $|-5.2672 +5.27 | = 0.0028$
Nevertheless, my answer is wrong and the correct answer must be $0.0072$
¿What is wrong in my development?, thanks in advance.
The question asks for the best approximation by excess; you provide, as you correctly note, an approximation by default. Even though it is a closer approximation than the approximation by excess, it's not what the question asked you use as the approximate value. Instead, you need to use the best approximation by excess as the approximate value.