What is the value of \( \frac{17!}{13!\cdot4!}-\frac{16!}{13!\cdot3!} \)?

Correct answer: 1820

After cancelling \(13!\), \(\frac{17!}{13!\cdot4!}=\frac{17\times16\times15\times14}{4!}=2380\). Similarly, \(\frac{16!}{13!\cdot3!}=\frac{16\times15\times14}{3!}=560\). Hence, the value of the expression is \(2380-560=1820\). \(2380\) is only the first term, so the second term must still be subtracted. Exam tip: expand the larger factorial only up to the smaller factorial, then cancel common factors before calculating.