Question

12/13-15/26
9/28-11/35
39/40-19/28

Answer 1

$frac{12}{13} - frac{15}{26} = frac{24}{26} - frac{15}{26} = frac{9}{26}$
$frac{9}{28} -frac{11}{35} =frac{45}{140} - frac{44}{140}= frac{1}{140}$
$frac{39}{40} - frac{19}{28} = frac{273}{280} - frac{190}{280}= frac{83}{280}$

Answer 2

Ничего, бывает

Answer 3

:)