Solve Carefully: 230 – 220 x 0.5 = You Probably Won’t Believe It, but the Answer Is 5!

Math-related brain teasers have a way of captivating social media users. Why is that? They offer a fun mental break from the stress of everyday life. Plus, puzzle lovers get an added challenge—they have to solve these puzzles entirely in their heads, without using a calculator or pen and paper.

The Puzzle:

230 – 220 x 0.5 = ?

First, let’s work it out:

Step-by-Step Solution:

1. 220 multiplied by 0.5 equals 110.
2. Then, subtract 110 from 230: $$230-110=120$$

So, the answer is 120, right? Yes, but there’s an interesting twist.

A Closer Look at 5 Factorial:

When we think of numbers in a different way, we find something interesting:

$$1\times 2\times 3\times 4\times 5=120$$

That’s equivalent to:

$$2\times 3\times 4\times 5=120$$

Or:

$$24\times 5=120$$

This means that the result, 120, is also the same as “5 factorial,” often written as 5!. In math, the exclamation mark after a number indicates a factorial, which means you multiply that number by all the positive whole numbers less than it (like 5 × 4 × 3 × 2 × 1).

Order of Operations Is Key:

In math, multiplication takes precedence over subtraction unless parentheses tell us otherwise. Here, we follow the order of operations (often remembered as PEMDAS—Parentheses, Exponents, Multiplication and Division, Addition and Subtraction). So first, multiply 220 by 0.5 to get 110, and then subtract it from 230, resulting in 120. That’s exactly why the answer is the same as 5!.