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
