[tex]\bf \cfrac{1}{4}\div \cfrac{4}{10}~~+~~\cfrac{5}{7}\div \cfrac{5}{7}\implies \cfrac{1}{4}\cdot \cfrac{10}{4}~~+~~\cfrac{5}{7}\cdot \cfrac{7}{5}\implies \cfrac{1\cdot 10}{4\cdot 4}+\cfrac{5\cdot 7}{7\cdot 5}
\\\\\\
\cfrac{10}{16}+\cfrac{35}{35}\implies \cfrac{10}{16}+1\implies \cfrac{(1\cdot 10)~+~16}{16}\implies \cfrac{26}{16}\implies \cfrac{13}{8}\implies 1\frac{5}{8}[/tex]
