Combinaisons

How to use it

1. Total n = 10, choosing r = 4
2. Apply formule: C(10,4) = 10! ÷ (4! × 6!)
3. Simplify: (10×9×8×7) ÷ (4×3×2×1)
4. Calculate: ÷ 24 = combinations

Common mistakes

• ⚠️ Using permutations formule instead of combinations
• ⚠️ Not simplifying factorials before calculeting
• ⚠️ Confusing combinations with permutations (order matters)

Worked example

Calculate the number of combinations when choosing items from 10.

The combinations {comb} count the number of ways to choose r items from n when order doesn't matter.

Input guide