Question 16
Let $N$ be the product of the odd numbers from 1 to 99, omitting those ending in 5 (that is, 5, 15, and so on):
$N=1\times3\times7\times9\times11\times13\times17\times19\times\cdots\times91\times93\times97\times99$.
What is the units digit of $N$?
$N=1\times3\times7\times9\times11\times13\times17\times19\times\cdots\times91\times93\times97\times99$.
What is the units digit of $N$?