10C4 represent the Combinations of 10 objects taken 4 at a time.
The formula for nCr is:
[tex]nCr= \frac{n!}{r!(n-r)!} [/tex]
In the given case, n=10 and r=4. Using these values we get:
[tex]10C4= \frac{10!}{4!(10-4)!} \\ \\
= \frac{10!}{4!*6!} \\ \\
=210 [/tex]
This means we can make 210 combinations of 10 objects taken 4 at a time.