Question 2
The numbers 1, 2,3,4,...,2015,2016 were written on a whiteboard. Tom chose
any two numbers a and b, erased them and then writes down their product ab.
He continued the same process until one number is left on the whiteboard. What
was the last digit of this number?
any two numbers a and b, erased them and then writes down their product ab.
He continued the same process until one number is left on the whiteboard. What
was the last digit of this number?