Bài 14.
\(a,-6\dfrac{1}{7}-\left(-7\dfrac{1}{6}\right)\)
\(=-\dfrac{43}{7}-\left(-\dfrac{43}{6}\right)\)
\(=-\dfrac{43}{7}+\dfrac{43}{6}\)
\(=-\dfrac{258}{42}+\dfrac{301}{42}\)
\(=\dfrac{43}{42}\)
\(---\)
\(b,-3\dfrac{1}{4}+\left(-2\dfrac{1}{3}\right)\)
\(=-\dfrac{13}{4}-\dfrac{7}{3}\)
\(=-\dfrac{39}{12}-\dfrac{28}{12}\)
\(=\dfrac{-67}{12}\)
\(---\)
\(c,-2\dfrac{1}{3}+\left(-1\dfrac{2}{7}\right)\)
\(=-\dfrac{7}{3}-\dfrac{9}{7}\)
\(=-\dfrac{49}{21}-\dfrac{27}{21}\)
\(=-\dfrac{76}{21}\)
Bài 15.
\(a,\left(-2\dfrac{1}{4}\right)+\dfrac{5}{2}\)
\(=-\dfrac{9}{4}+\dfrac{5}{2}\)
\(=-\dfrac{9}{4}+\dfrac{10}{4}\)
\(=\dfrac{1}{4}\)
\(---\)
\(c,-3-\left(-2\dfrac{2}{5}\right)\)
\(=-3-\left(-\dfrac{12}{5}\right)\)
\(=-3+\dfrac{12}{5}\)
\(=\dfrac{-15}{5}+\dfrac{12}{5}\)
\(=-\dfrac{3}{5}\)
\(---\)
\(c,\left(-1\dfrac{1}{3}\right)+2\dfrac{1}{2}\)
\(=-\dfrac{4}{3}+\dfrac{5}{2}\)
\(=-\dfrac{8}{6}+\dfrac{15}{6}\)
\(=\dfrac{7}{6}\)
#\(Toru\)
