其它
The ones digit of $$1!+2!+3!+···+100!$$ is~\uline{~~~~~~~~~~}~. 
Overseas Competition->Knowledge Point->Calculation Modules->Operations through Formulas
$$\textasciitilde\textasciitilde\textasciitilde\textasciitilde1+1\times 2+1\times 2\times 3+1\times 2\times 3\times 4$$  $$=1+2+6+24$$  $$=33$$ 