Question Number 165383 by naka3546 last updated on 01/Feb/22
$${Find}\:\:{the}\:\:{value}\:\:{of}\:\:{this}\:\:{expression} \\ $$$$\left(−\mathrm{1}\right)\left(\mathrm{2}^{\mathrm{2}} −\mathrm{1}\right)+\frac{\left(\mathrm{3}^{\mathrm{2}} −\mathrm{2}\right)}{\mathrm{2}!}\:−\:\frac{\left(\mathrm{4}^{\mathrm{2}} −\mathrm{3}\right)}{\mathrm{3}!}\:+\:\ldots+\:\frac{\left(\mathrm{2019}^{\mathrm{2}} −\mathrm{2018}\right)}{\mathrm{2018}!} \\ $$