0 ! = 1 why ? इसे जनने के लिए हम कुछ समझने का प्रयास करते हैं 5 ! = means 5 × 4 × 3 × 2 × 1 = 120.  120 ÷ 5 = 24 which is the sum of next 4 ! 4 ! = means 4 × 3 × 2 × 1 = 24.  24 ÷ 4 = 6 which is the sum of next 3 ! 3 ! =   means  3 × 2 × 1 = 6.   6 ÷ 3 = 2 which is the…