Factorial Math Example 1

Solution

1. 1
   Recall the factorial definition: $n! = n \times (n-1) \times \cdots \times 2 \times 1$. Write out $7!$: $$7! = 7 \times 6 \times 5 \times 4 \times 3 \times 2 \times 1$$
2. 2
   Multiply step by step: $7 \times 6 = 42$, then $42 \times 5 = 210$, then $210 \times 4 = 840$, then $840 \times 3 = 2520$.
3. 3
   Complete the product: $2520 \times 2 = 5040$, so $7! = 5040$.