← Back to: Math Glossary

What is a Rational Number?


A Rational Number is any number that can be written as a fraction — one number over another. Even if it looks like a decimal, if it can be written as a fraction, it’s rational!

Examples of rational numbers:

• 1/2

• 4 (which is the same as 4/1!)

• 0.75 (same as 3/4)

• –2/3

• 5.0 (equal to 5/1)

If the decimal stops or repeats, it’s rational.


Helpful Rule:

If you can write it as a ratio (one number divided by another), it's rational!


❌ NOT rational?

Numbers like π or √2 — they can’t be written as a clean fraction, so they’re called irrational.

Try This Game:

“Rational Roundup!”

1️⃣ Write a mix of numbers on flashcards: 0.5, 3, π, 1/3, 0.333…, √2

2️⃣ Ask your partner to pick out all the rational ones

3️⃣ Turn decimals into fractions and explain why they are (or aren’t) rational!

Rational numbers show up everywhere — in money, measuring, and dividing things up. Learning them helps you with fractions, decimals, and real-world math!


Practice Time!

Think you're a number ninja? Try our Missing Numbers Quiz! 🎯