4 1/5*5/7-0,3:0,4= 21/5*5/7-3/10:4/10= 3-3/10*10/4= 3-3/4=2 1/4

[latex]4frac{1}{5}cdotfrac{5}{7}-0,3:0,4=frac{21}{5}cdotfrac{5}{7}-frac{3}{10}:frac{4}{10} = frac{21}{7}-frac{3}{10}cdotfrac{10}{4}=3-frac{3}{4}=2frac{1}{4}=2,25[/latex]