a) 1/7 - (-3/14) + 1/2
= 2/14 + 3/14 + 7/14
= 12/14
= 6/7
b) 2/5 + 1/5 . (-3/4)
= 2/5 - 3/20
= 8/20 - 3/20
= 5/20
= 1/4
c) 4/5 - (-2/7) - 7/10
= 56/70 + 20/70 - 49/70
= 27/70
d) 3/7 + (-5/2) + (-3/5)
= 30/70 - 175/70 - 43/70
= -188/70
= -94/35
a) \(\dfrac{1}{7}-\left(-\dfrac{3}{14}\right)+\dfrac{1}{2}\)
\(=\dfrac{1}{7}+\dfrac{3}{14}+\dfrac{1}{2}\)
\(=\dfrac{2}{14}+\dfrac{3}{14}+\dfrac{7}{14}\)
\(=\dfrac{12}{14}=\dfrac{6}{7}\)
b) \(\dfrac{2}{5}+\dfrac{1}{5}.\left(-\dfrac{3}{4}\right)\)
\(=\dfrac{2}{5}+\left(-\dfrac{3}{20}\right)\)
\(=\dfrac{8}{20}+\left(-\dfrac{3}{20}\right)\)
\(=\dfrac{5}{20}=\dfrac{1}{4}\)
c) \(\dfrac{4}{5}-\left(-\dfrac{2}{7}\right)-\dfrac{7}{10}\)
\(=\dfrac{4}{5}+\dfrac{2}{7}+\left(-\dfrac{7}{10}\right)\)
\(=\left[\dfrac{4}{5}+\left(-\dfrac{7}{10}\right)\right]+\dfrac{2}{7}\)
\(=\left[\dfrac{8}{10}+\left(-\dfrac{7}{10}\right)\right]+\dfrac{2}{7}\)
\(=\dfrac{1}{10}+\dfrac{2}{7}\)
\(=\dfrac{7}{70}+\dfrac{20}{70}\)
\(=\dfrac{27}{70}\)
d) \(\dfrac{3}{7}+\left(-\dfrac{5}{2}\right)+\left(-\dfrac{3}{5}\right)\)
\(=\dfrac{3}{7}-\dfrac{5}{2}-\dfrac{2}{5}\)
\(=\left(-\dfrac{29}{14}\right)-\dfrac{3}{5}\)
\(=-\dfrac{188}{70}=-\dfrac{94}{35}\)
