Have you ever seen a simple math puzzle online that divides everyone in the comments?
This classic equation looks easy at first glance, but it hides a clever trick.
Let’s look at the problem together:
230 – 220 ÷ 2 = ?
One person claims the correct answer is 120.
On the other hand, a Math PhD claims the answer is 5!
So, who is actually right?
Let’s solve the problem step by step to find out.
First, we must follow the standard order of mathematical operations (PEMDAS / BODMAS).
This rule tells us to perform division before subtraction.
So, we divide 220 by 2 first.
220 ÷ 2 = 110.
Next, we subtract 110 from 230.
230 – 110 = 120.
Based on basic arithmetic, the numeric result of the equation is indeed 120.
This means the first person calculated the number correctly.
Does this mean the Math PhD made a mistake?
Not at all.
The key to the PhD’s answer lies in punctuation and mathematical notation.
Notice how the PhD wrote their answer: “5!”
In mathematics, the exclamation mark (!) is not just for excitement.
It represents the factorial function.
A factorial means multiplying a whole number by every whole number below it down to 1.
So, what is the value of 5! (5 factorial)?
5! = 5 × 4 × 3 × 2 × 1.
Let’s do the math:
5 × 4 = 20.
20 × 3 = 60.
60 × 2 = 120.
120 × 1 = 120.
Therefore, 5! is equal to 120.
The numerical value of 120 and the mathematical expression 5! are identical.
In conclusion, both answers are completely correct!
The first person stated the direct numerical answer.
The Math PhD expressed the exact same number using factorial notation.
It is a clever math joke that reminds us to look closely at every symbol!
