Problem:
What is 10!−7!⋅6! ?
Answer Choices:
A. −120
B. 0
C. 120
D. 600
E. 720
Solution:
Note that
10!−7!⋅6!=7!⋅(10⋅9⋅8−6!)=7!⋅(720−720)=(B)0​
The problems on this page are the property of the MAA's American Mathematics Competitions