Question

-1/21 + -1/28

Answer 1

\(-\dfrac{1}{21}+\dfrac{-1}{28}=-\dfrac{1}{12}\)

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Answer 2

\(\dfrac{-1}{21}\) + \(\dfrac{-1}{28}\) = \(\dfrac{-4+\left(-3\right)}{84}\) = \(\dfrac{-7}{84}\) = \(\dfrac{-1}{12}\)