Without parentheses, the expression 8 plus 30 divided by 2 plus 4 equals 27. Rewrite this expression with parentheses so that it equals 13; then 23

For 13: 8 + 30 / (2+4). Bidmas means the 30 divided by 6 will occur before the 8 is added. So it is done as 8 plus 30 divided by 6, which is 8 plus 5, giving 13.

For 23: (8+30) / 2 + 4. Againm bidmas means the / 2 will occur before the + 4 so what happens is 38 divided by 2 to give 29, then add 4 to get 23.