230 – 220 x 0.5 = 5!

This is a cleverly expressed problem. It is easy to get the correct answer for a totally invalid reason.

The problem!

230 – 220 x 0.5 =

Remember BODMAS – Brackets, Of, Division, Multiplication, Addition, Subtraction.

230 – 220 x 0.5 =

230 – 110 =

120 =

The answer is 120?

Yes, but…

1 * 2 * 3 * 4 * 5 =

2 * 3 * 4 * 5 =

24 * 5 =

120 =

5 factorial =

5!

Multiplications must be done before subtractions (unless bracketing directs otherwise, which it does not here), so first we multiply 220 by 0.5, and half of 220 is 110, subtract that 110 from 230 to get 120, which is the same as 5 × 4 × 3 × 2 × 1, which is 5 factorial (the meaning of 5!—the exclamation point indicating the factorial operator and not excitement).