Question

`27- {13 + 4 - (8 + 4 - bar(1 + 3))}`

Answer 1

`27- {13 + 4 - (8 + 4 - bar(1 + 3))}`

The overline indicates grouping: `bar(1+3) = 1+3=4`

27 − {13 + 4 − (8 + 4 − 4)}

8 + 4 − 4 = 8

Substitute: 27 − {13 + 4 − 8}

13 + 4 − 8 = 9

Substitute: 27 − 9

27 − 9

= 18