When you add all the numbers together, then divide it by how many numbers there are. Example: (21+44+72+90+1) divided by 5= 45 remander 3.
The middle number from least to greatest. Example: 12,33,(56),77,110
The number in a sequence that appears most often. Example: 12,22,(83),45,(83),18
Take the smallest number and subtract it from the largest number, so really just find the difference. Example: 85-11=(74)