NUM006 · Numbers & number systems · Classes 6–12
Number Systems
Number sets nest inside one another: ℕ ⊂ 𝕎 ⊂ ℤ ⊂ ℚ ⊂ ℝ ⊂ ℂ.
Number Systems📐 Formula
Natural 1, 2, 3 …; whole adds 0; integers add negatives; rationals p/q; reals add irrationals (√2, π); complex add i
✏️ Worked example
−5 is an integer but not a whole number; √2 is real but not rational.
🌍 Where it is used
Every measurement, account balance and calculation uses them.
❓ Quick check
Which is irrational?