Identify rational and irrational numbers

1️⃣ What are Numbers?

Numbers are symbols we use to count, measure, and label things.
They can be classified into Rational and Irrational numbers.


2️⃣ Rational Numbers (✅)

A rational number is any number that can be written as a fraction p/q, where:

  • p = integer
  • q = non-zero integer (q ≠ 0)

🟢 Examples of Rational Numbers:

  • Fractions: 1/2, -3/4
  • Whole numbers: 5, 0, -7
  • Decimals that terminate or repeat: 0.75, 0.333…

📝 Key Points:

  • ✅ Can be written as fractions
  • ✅ Decimal form terminates (stops) or repeats
  • ✅ Can be positive or negative

3️⃣ Irrational Numbers (❌)

An irrational number cannot be written as a fraction.
Its decimal form never ends and never repeats.

🔴 Examples of Irrational Numbers:

  • √2, √3, √5
  • π (Pi ≈ 3.14159…)
  • e (Euler’s number ≈ 2.718…)

📝 Key Points:

  • ❌ Cannot be written as a fraction
  • ❌ Decimal form goes on forever
  • Non-repeating decimals

4️⃣ Quick Tips to Identify ✅ vs ❌

ClueRationalIrrational
Fraction form exists?✅ Yes❌ No
Decimal form?✅ Terminates/Repeats❌ Non-terminating/non-repeating
Examples2, -3, 1/4, 0.666…√2, π, √3

5️⃣ Fun Emojis Trick to Remember

  • Rational = “R for Regular” → neat fractions, repeats nicely ✨
  • Irrational = “I for Infinite” → decimals never end 🌌

Learn with an example

Let’s practice!🖊️