Can You Solve This Math Puzzle in 10 Seconds? Most People Miss One Simple Rule
A short math puzzle is making people stop and think twice.
At first glance, the equation looks almost too easy. But there is a catch: getting the correct answer depends on following the order of operations rather than simply calculating from left to right.
The challenge is simple:
7 × 7 ÷ 7 − 7 + 7 = ?
Can you solve it in 10 seconds without looking at the answer?
Take a moment before continuing.
The Rule That Makes the Difference
When an expression contains several mathematical operations, they must be performed in the correct order.
A commonly used memory aid is PEMDAS:
- P — Parentheses
- E — Exponents
- M — Multiplication
- D — Division
- A — Addition
- S — Subtraction
There is an important detail here: multiplication and division have the same priority, so they are evaluated from left to right. Addition and subtraction also have the same priority and are evaluated from left to right.
Let’s Solve the Puzzle
Start with:
7 × 7 ÷ 7 − 7 + 7
First, perform the multiplication:
7 × 7 = 49
The expression becomes:
49 ÷ 7 − 7 + 7
Now perform the division:
49 ÷ 7 = 7
So we have:
7 − 7 + 7
Next, work from left to right with subtraction and addition:
7 − 7 = 0
Then:
0 + 7 = 7
The Correct Answer Is: 7
That’s the part that makes this puzzle interesting. The source article states 55, but its worked solution changes the original expression into 49 − 1 + 7, which does not follow from the displayed equation 7 × 7 ÷ 7 − 7 + 7.
