Chapter 1 - Introduction to Algebraic Expressions - 1.7 Multiplication and Division of Real Numbers - 1.7 Exercise Set - Page 58: 108

$-\dfrac{2}{7}$

The given expression, $ \left( -\dfrac{4}{7} \right)-\left( -\dfrac{2}{7} \right) $, simplifies to \begin{array}{l}\require{cancel} -\dfrac{4}{7}+\dfrac{2}{7} \\\\= \dfrac{-4+2}{7} \\\\= \dfrac{-2}{7} \\\\= -\dfrac{2}{7} .\end{array}