5-{3+2[5-4 (64:8) ]-12}

You must follow the correct order of operations.

5 - {3 + 2[5 - 4 (64 : 8) ] - 12} =

Start by doing the division in the innermost parentheses.

= 5 - {3 + 2[5 - 4 (8) ] - 12}

Now do the multiplication of 4 and 8.

= 5 - {3 + 2[5 - 32] - 12}

Now do the subtraction in the square brackets.

= 5 - {3 + 2[-27] - 12}

Multiply 2 by - 27.

= 5 - {3 - 54 - 12}

Now do 3 - 54.

= 5 - {-51 - 12}

-51 - 12 is next.

= 5 - {-63}

= 5 + 63

= 68

Answer: 68

The answer that I got was 29