2/5 + 21/10 + 1/15 =
$\dfrac{2}{5}+ \dfrac{21}{10}+\dfrac{1}{15} =\dfrac{(2\cdot 6)+(21\cdot 3)+1\cdot 2}{30}=$
$\dfrac{12+63+2}{30}= 77/30$
Home
Profilo
Menu