a; \(\frac35+\frac{14}{7}+\frac{4}{10}\)
= \(\frac35\) + 2 + \(\frac25\)
= (\(\frac35\) + \(\frac25\)) + 2
= 1+ 2
= 3
b; \(\frac27+\frac37+\frac47+\frac57+\frac67\)
= \(\frac57+\frac47+\frac57+\frac67\)
= \(\frac97+\frac57+\frac67\)
= \(\frac{14}{7}+\frac67\)
= \(\frac{20}{7}\)