\(1,\dfrac{-1}{4}+\dfrac{4}{15}+\dfrac{-3}{4}\)
\(=\left(\dfrac{-1}{4}+\dfrac{-3}{4}\right)+\dfrac{4}{15}\)
\(=\dfrac{-4}{4}+\dfrac{4}{15}\)
\(=\left(-1\right)+\dfrac{4}{15}\)
\(=\dfrac{-15}{15}+\dfrac{4}{15}\)
\(=\dfrac{-11}{15}\)
\(2,\dfrac{2}{3}+\dfrac{-1}{3}+\dfrac{7}{15}\)
\(=\left(\dfrac{2}{3}+\dfrac{-1}{3}\right)+\dfrac{7}{15}\)
\(=\dfrac{1}{3}+\dfrac{7}{15}\)
\(=\dfrac{5}{15}+\dfrac{7}{15}\)
\(=\dfrac{12}{15}=\dfrac{4}{5}\)
\(3,\dfrac{4}{5}-\left(\dfrac{-2}{5}\right)-\dfrac{7}{10}\)
\(=\dfrac{4}{5}+\dfrac{2}{5}-\dfrac{7}{10}\)
\(=\left(\dfrac{4}{5}+\dfrac{2}{5}\right)-\dfrac{7}{10}\)
\(=\dfrac{6}{5}-\dfrac{7}{10}\)
\(=\dfrac{12}{10}-\dfrac{7}{10}\)
\(=\dfrac{5}{10}=\dfrac{1}{2}\)
`1, (-1)/4+4/5+(-3)/4`
`=(-1/4-3/4)+4/5`
`=-4/4+4/5`
`=-1+4/5`
`=-1/5`
`2, 2/3+(-1)/3+7/15`
`= 1/3 + 7/15`
`= 5/15+7/15`
`= 12/15`
`= 4/5`
`3, 4/5-((-2)/5)-7/10`
`= 8/10 + 4/10 - 7/10`
`= (8+4-7)/10`
`= 5/10`
`= 1/2`
`4, 3/7 - 2/3 + 4/7`
`= (3/7+4/7)-2/3`
`=7/7-2/3`
`=1-2/3`
`=1/3`
`5,2/3+1/4-1/3`
`=(2/3-1/3)+1/4`
`=1/3+1/4`
`=4/12+3/12`
`=7/12`
`6, 3/5-5/4+2/5`
`=(3/5+2/5)-5/4`
`=5/5-5/4`
`=1-5/4`
`=-1/4`
\(4,\dfrac{3}{7}-\dfrac{2}{3}+\dfrac{4}{7}\)
\(=\left(\dfrac{3}{7}+\dfrac{4}{7}\right)-\dfrac{2}{3}\)
\(=\dfrac{7}{7}-\dfrac{2}{3}\)
\(=1-\dfrac{2}{3}\)
\(=\dfrac{3}{3}-\dfrac{2}{3}\)
\(=\dfrac{1}{3}\)
\(5,\dfrac{2}{3}+\dfrac{1}{4}-\dfrac{1}{3}\)
\(=\left(\dfrac{2}{3}-\dfrac{1}{3}\right)+\dfrac{1}{4}\)
\(=\dfrac{1}{3}+\dfrac{1}{4}\)
\(=\dfrac{4}{12}+\dfrac{3}{12}=\dfrac{7}{12}\)
\(6,\dfrac{3}{5}-\dfrac{5}{4}+\dfrac{2}{5}\)
\(=\left(\dfrac{3}{5}+\dfrac{2}{5}\right)-\dfrac{5}{4}\)
\(=\dfrac{5}{5}-\dfrac{5}{4}\)
\(=1-\dfrac{5}{4}\)
\(=\dfrac{4}{4}-\dfrac{5}{4}=\dfrac{-1}{4}\)
