20.只列式不计算食堂运来360千克大米,___,食堂运来多少千克面粉?
①运来的面粉是大米的$\frac{1}{5}$,列式为:360×$\frac{1}{5}$
②运来的面粉比大米多$\frac{1}{5}$,列式为:360×(1+$\frac{1}{5}$)
③运来的面粉比大米少$\frac{1}{5}$,列式为:360×(1-$\frac{1}{5}$)
④运来的大米是面粉的$\frac{1}{5}$,列式为:360÷$\frac{1}{5}$
⑤运来的大米比面粉多$\frac{1}{5}$,列式为:360÷(1+$\frac{1}{5}$)
⑥运来的大米比面粉少$\frac{1}{5}$,列式为:360÷(1-$\frac{1}{5}$).