Hey guys

Just need to know, on the SAT/PSAT, a phrase called "Units digit" keeps popping up and I have no idea what it means...Here is an example problem

"The unit digit of the sum of three consecutive integers is 8. What is the units digit of the least of these integers?"

A) 4

B) 5

C) 6

D) 7

E) 8

I know this is noobie stuff but just need to know what it means real quick

Thanks alot

Derg