Evaluate the expression.

4! • 3!

The answer is 4!·3!=144
the ! is interesting. it goes like this:
1!= 1
2!=2
3!=6
4!=24
this happens because each ! will multiply the number by the answer to the number before it. it is easier to show you though.
1!=1 because 0!=1, and 1*1=1
2!=2 because 1!=1, and 2*1=2
3!=6 because 2!=2, and 3*2=6
4!=24 because 3!=6, and 4*6=24.
so 4!=[(24)*(6)]=3!
24*6=144