Question Number 127698 by MathSh last updated on 01/Jan/21
$$−\mathrm{1}!+\mathrm{2}!−\mathrm{3}!−\mathrm{5}!+\mathrm{6}!−\mathrm{4}!!+\mathrm{7}!!+\mathrm{8}!!+\mathrm{9}!!=\mathrm{2021} \\ $$$${Happy}\:{New}\:{Year}! \\ $$
Commented by talminator2856791 last updated on 04/Jan/21
$$\:\mathrm{are}\:\mathrm{you}\:\mathrm{sure}\:\mathrm{this}\:\mathrm{is}\:\mathrm{true}? \\ $$$$\:\mathrm{9}!!\:\mathrm{seems}\:\mathrm{much}\:\mathrm{larger}\:\mathrm{than}\:\mathrm{any}\:\mathrm{of}\:\mathrm{the}\:\mathrm{other}\:\mathrm{numbers}. \\ $$
Commented by talminator2856791 last updated on 04/Jan/21
$$\:\mathrm{how}\:\mathrm{did}\:\mathrm{you}\:\mathrm{find}\:\mathrm{this}? \\ $$