The Strange History of Mathematical Symbols

Mathematics is full of mystery—not just in its theories but in its symbols too. We use +, =, and x every day without questioning where they came from. But their origins are surprisingly strange, filled with forgotten geniuses, accidental inventions, and even a bit of confusion.

 

Let’s uncover the hidden stories behind the math symbols we take for granted.

 

1. The Plus (+) and Minus (−) Signs Were Invented by Merchants, Not Mathematicians

Imagine doing math without + and −. Before the 15th century, people actually wrote out equations in words! Instead of writing "8 + 5," they’d say "8 and 5 more."

So, where did "+" and "−" come from? Not from mathematicians, but from German merchants in the late 1400s!

In 1489, a German mathematician named Johannes Widmann published a book on trade and accounting. Instead of writing "profit" and "loss," he used "+" for extra stock and "−" for missing stock.

The symbols spread like wildfire among bookkeepers and eventually became standard in math!

2. The Equal Sign (=) Used to Be a Lot Longer!

Have you ever stopped to think about why we use "=" to mean equal?

In the 1500s, solving an equation was a tedious task. Mathematicians had to write "is equal to" over and over again. One man had enough.

In 1557, Welsh mathematician Robert Recorde introduced "=" because he was tired of writing "is equal to" repeatedly.

He explained: "I choose two parallel lines because no two things can be more equal."

But here’s the twist—his original symbol was ridiculously long: "============" instead of just "="! 

Luckily, later mathematicians shortened it to the version we use today.

 

3. The Multiplication Sign (×) Was Almost a Different Shape

The "×" symbol is everywhere, but it wasn’t always the go-to for multiplication.

In the early 1600s, John Napier, the inventor of logarithms, used a dot (·) for multiplication. Some mathematicians still use it today (like a · b).

In 1631, English mathematician William Oughtred introduced "×" as the standard.

But funnily enough, many mathematicians objected to "×" because it looked too much like the letter x!

That’s why, in algebra, we often use "·" instead of "×"—so we don’t confuse it with a variable.

 

4. Why Do We Use "X" for the Unknown?

Speaking of x, why do we always use it to represent an unknown number?

The answer comes from an old Arabic word: "شيء" (pronounced "shay’"), which means "something" or "thing."

In the 9th century, Persian mathematician Al-Khwarizmi wrote algebraic equations using "shay’" for unknown values.

When his works were translated into Spanish, the word became "xay" because Spanish scholars struggled to pronounce "sh."

Over time, "xay" was shortened to just "x", and the tradition stuck!

At Last:

Math Symbols Have a Wild History. Next time you solve an equation, remember you’re using symbols that merchants, bookkeepers, and even frustrated mathematicians invented centuries ago. Math isn’t just about numbers—it’s also a story of human creativity, mistakes, and clever shortcuts.