Example 1
If we don't care about order, how many combinations are there if we have 5 things and take 3 of them?
Example 2
If we don't care about order, how many combinations are there if we have 7 things and take 2 of them?
Example 3
If we don't care about order, how many combinations are there if we have 10 things and take 7 of them?
Example 4
Find the combination: 
.
Example 5
Find the combination: 
.
Example 6
Find the combination: 
.
Example 7
Find the combination: 
.
Example 8
Find the combination: 
.