Mean-add up all the numbers and divided by the amount of numbers there are.
Median-list numbers in order from least to greatest, then find the one in the middle. Ex. 3, 4, 5. 4 would be the middle number. If there's an even number, get the two in the middle, add them and divide by two. Ex. 3,4,5,6. 4+5=9 divided by 2=4.5
Mode-the number that shows up the most.