Simplify, following the order of operations: 23 + 5 * 10 : 2 - 33 + (11 - 8)

The order of operations is parentheses, exponents, multiply and divide, add and subtract

put the things being multiplied and divided in parentheses

23 + (5 * 10/2) - 33 + (11-8)

solve the things in the parentheses

23 + (25) - 33 + (3)

then combine the terms

18