Question

What is the maximum value of an expression 5−8+7×4−8+9 that can be obtained by placing pairs of parentheses into it?

For example,
((5−8)+7)×4−8+9=17,
(5−(8+7))×(4−(8+9))=130.
But the maximum value is even larger!​

Answer 1

I don’t know if it’s correct. But my reasoning is as follows:

5-8(+7)x(4-8)(+9)=2021

Method:
5-8x7x(-4)x9
5+2016=2021

when there is no sign between the brackets it is implied that there is a multiplication.

furthermore, the problem does not give any constraint on where to put the parentheses so I put as you see (+7) because in maths you can do this.

I hope you can understand what I said and I hope my reasoning is correct.