Algebra
posted by PRIDE .
All the even numbers from 2 to 98 inclusive, except those ending in
0, are multiplied together. What is the rightmost digit, that is,
the units digit of the product?

2*4*6*8 = 384, and that last digit "4" will be the last digit of each group of _2,_4,_6,_8 that gets multiplied. After multiplying 10 numbers that end in 4, the last number will be the same as the last digit of 4^10, which is 6.

What two numbers multiplied together equals 5040 and added together equals 98