Question

FACTORIAL EXPLANATION- Explain the best way to evaluate 900!/899! without a calculator.

Answer 1

900! is really 900 * 899 * 898 * 897 * 896 * 895 ......... * 3 * 2 * 1.

899 is really 899 * 898 * 897 * 896 * 895 ......... * 3 * 2 * 1.

$\bf \cfrac{900!}{899!}\implies \cfrac{900\cdot 899!}{899!}\implies 900\cdot \cfrac{899!}{899!}\implies 900\cdot 1\implies 900$