Question

give two examples that show how using parentheses can change the order in wich operations are performed in an expression

Answer 1

(4 + 2) / 36 = 1/6
4 + 2/36 = 4 + 1/18 = 72/18 + 1/18 = 73/18

(5 - 3) / 4 = 1/4
5 - 3/4 = 20/4 - 3/4 = 17/4

Answer 2

This is because of the order of operations:
Parentheses
Exponent
Divide
Multiply
Add
Subtract

Note that parentheses are the first, so it will affect everything after it.

Examples:
2(5+4)= 2x9= 18
(2x5)+4= 10+4= 14

5/(2+3)= 5/5= 1
(5/2)+3= 2.5+3= 5.5