I'm worried that this will be a spanner in the works when I'm using a calculator in an exam , I know that $-2^2= 4$ since $(-2) \cdot (-2) = 4 $. So why does my calculator show it as negative 4 ? Does anyone know if there is a way to reset my calculator so it doesn't do this? The make and model is Casio fx-83ES.
There is a difference between $-2^2$ and $(-2)^2$ In the first examples you square the number two and then you apply the negative. In the second example you sqaure the number negative two then you get the desired reuslt, 4
This is a really simple error to correct. It's order of operations: $-2^2=-(2^2)=-4$. Your calculator is correct, just use parentheses around $-2$. $(-2)^2=4≠-2^2$.
Note that $-2^2$ is different than $(-2)^2$, which you intend.
Reviewing the order of operations, exponentiation comes before multiplication. $-2^2 = -1 \cdot 2^2 = -1 \cdot 4 = -4$.
However $(-2)^2$ is evaluated as $(-2)^2 = 4$.