Question

Calcule:

a) \frac{1}{2} + \frac{3}{7} =

b) - \frac{2}{3} + \frac{4}{9} =

c) \frac{5}{3} + (-\frac{1}{2}) =

d) -\frac{1}{3} + (-1) =

Answer 1

$a)\ \frac{1}{2} + \frac{3}{7} \ \ \ \ \ \ \ \ mmc \ de\ 2\ e\ 7\ =14\\\\\\ \frac{14:2.1+14:7.3}{14} = \frac{7+6}{14} =\boxed{\boxed{ \frac{13}{14} }}\\\\\\\\\\\\\\\\b)\ - \frac{2}{3} + \frac{4}{9} \ \ \ \ \ \ \ \ mmc\ de\ 3\ e\ 9=9\\\\\\ \frac{-(9:3.2)+9:9.4}{9} = \frac{-6+4}{4} =- \frac{2}{4} =\boxed{\boxed{- \frac{1}{2} }}$





$c)\ \frac{5}{3} - \frac{1}{2} \ \ \ \ \ mmc\ de\ 3\ e\ 2=6\\\\\\ \frac{6:3.5-6:2.1}{6} = \frac{10-3}{6} =\boxed{\boxed{ \frac{7}{6} }}\\\\\\\\\\\\\\\\d)\ - \frac{1}{3} -1= -\frac{1}{3} - \frac{1}{1} \ \ \ \ \ \ \ \ \ \ mmc\ de\ 3\ e\ 1=3\\\\\\ -\frac{3:3.1+3:1.3}{3} =- \frac{1+3}{3} =\boxed{\boxed{- \frac{4}{3} }}\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ ok$