At first glance, these two calculations look almost identical. On one phone, the expression reads:
130 + 100 × 5
while on the other, it says:
100 + 130 × 5
Yet the answers are completely different. One calculator shows 630, while the other displays 750. Surprisingly, neither calculator is wrong. The confusion comes from a basic but extremely important math rule known as the order of operations.
In mathematics, multiplication is always performed before addition unless parentheses change the order. Many people naturally try to calculate from left to right, but calculators follow the correct mathematical priority automatically.
Here’s how the first equation works:
130 + 100 × 5
The calculator first solves:
100 × 5 = 500
Then it adds 130:
130 + 500 = 630
Now look at the second equation:
100 + 130 × 5
Again, multiplication comes first:
130 × 5 = 650
Then the calculator adds 100:
100 + 650 = 750
Even though the numbers are similar, changing their position completely changes the result because the multiplication affects different numbers in each equation.
This is one of the most common math misunderstandings people encounter online. Many assume calculators are malfunctioning when they see different answers, but the real explanation is simply the mathematical rules operating behind the scenes.
The easiest way to avoid confusion is to remember this basic principle:
Multiplication and division always come before addition and subtraction.
If you want calculations to happen in a different order, you must use parentheses. For example:
(130 + 100) × 5
would produce an entirely different answer because the addition would happen first.
Small details in math can completely change the outcome — and this image is the perfect example of why understanding the order of operations matters so much in everyday calculations.