18
When evaluating an expression with mixed operations
If multiplication and division are in the expression then evaluate them from left to right
This is also the case for addition and subtraction, hence
15 - 12 ÷ 6 ÷ 2 × 4 + 7
= 15 - 2 ÷ 2 × 4 + 7 ( evaluating 12 ÷ 6 )
= 15 - 1 × 4 + 7 ( evaluating 2 ÷ 2 )
= 15 - 4 + 7 ( evaluating 1 × 4 )
= 11 + 7 ( evaluating 15 - 4 )
= 18 ( evaluating 11 + 7 )