Hi Pori,

In many cases English is not as precise as mathematics. I'm not sure if you want the number which is the square of minus 5 or the number which is minus the square of 5. The first would be $(-5)^2 = (-5) \times (-5) = 25.$ The latter would be $- 5^2 = - 25.$ It is a convention in mathematics that exponentiation (powers), multiplication and division are performed before addition and subtraction and hence with $-5^2$ I perform $5^2 = 25$ before applying the negation.

I hope this helps,
Penny