Here is an example,
Kate had a test and one of the questions were 8 dived by 2 +( 6+7)+3. She answered by saying it was 13.625 . When the teacher graded it she marked it wrong then handed it to Kate saw that it was wrong. She wondered why so she asked the teacher and said why she got it wrong and explained that the parenthesis are show that you need to solve the number in it first before you do anything else. Then Kate tried to solve it again and got 20.
Hope this helps and sorry it took me long to reply
