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\(E=\dfrac{-1}{3}-\dfrac{2}{3}+\dfrac{2}{5}-\dfrac{3}{5}+\dfrac{1}{5}=-1\)
Ta có: \(\dfrac{-4}{12}+\dfrac{18}{45}+\dfrac{-6}{9}+\dfrac{21}{35}+\dfrac{6}{30}\)
\(=\dfrac{-1}{3}+\dfrac{-2}{3}+\dfrac{2}{5}+\dfrac{3}{5}+\dfrac{6}{30}\)
\(=-1+1+\dfrac{1}{5}\)
\(=\dfrac{1}{5}\)
Lời giải:
$=\frac{-9}{10}+\frac{13}{10}+(\frac{6}{11}-\frac{9}{11})$
$=\frac{13-9}{10}+\frac{6-9}{11}=\frac{4}{10}-\frac{3}{11}$
$=\frac{7}{55}$
\(\dfrac{7}{21}+\dfrac{-9}{36}=\dfrac{1}{3}+\dfrac{-1}{4}=\dfrac{4}{12}+\dfrac{-3}{12}=\dfrac{1}{12}\)
\(\dfrac{-12}{18}+\dfrac{-21}{35}=\dfrac{-2}{3}+\dfrac{-3}{5}=\dfrac{-10}{15}+\dfrac{-9}{15}=\dfrac{-19}{15}\)
\(\dfrac{-18}{14}+\dfrac{15}{-21}=\dfrac{-9}{7}+\dfrac{-5}{7}=\dfrac{-14}{7}=-2\)
\(\dfrac{3}{21}+\dfrac{-6}{42}=\dfrac{1}{7}+\dfrac{-1}{7}=0\)
a) A= \(\dfrac{4}{7}+\dfrac{3}{4}+\dfrac{2}{7}+\dfrac{5}{4}+\dfrac{1}{7}\)
= \(\left(\dfrac{4}{7}+\dfrac{2}{7}+\dfrac{1}{7}\right)+\left(\dfrac{3}{4}+\dfrac{5}{4}\right)\)
= \(\dfrac{4+2+1}{7}+\dfrac{3+5}{4}\)
= \(\dfrac{7}{7}+\dfrac{8}{4}\) = \(1+2\) = \(3\)
b) B= \(\dfrac{-4}{12}+\dfrac{18}{45}+\dfrac{-6}{9}+\dfrac{-21}{35}+\dfrac{6}{30}\)
= \(\dfrac{-1}{3}+\dfrac{2}{5}+\dfrac{-2}{3}+\dfrac{-3}{5}+\dfrac{1}{5}\)
= \(\left(\dfrac{-1}{3}+\dfrac{-2}{3}\right)+\left(\dfrac{2}{5}+\dfrac{-3}{5}+\dfrac{1}{5}\right)\)
= \(\dfrac{\left(-1\right)+\left(-2\right)}{3}+\dfrac{2+\left(-3\right)+1}{5}\)
= \(\dfrac{-3}{3}+\dfrac{0}{5}\) = \(-1+0\) = \(-1\)
a: \(=\dfrac{-2}{12}-\dfrac{5}{12}+\dfrac{7}{12}=0\)
b: \(=\left(\dfrac{4}{45}-\dfrac{1}{45}+\dfrac{7}{45}+\dfrac{4}{45}-\dfrac{2}{45}-\dfrac{9}{45}\right)=\dfrac{3}{45}=\dfrac{1}{15}\)
\(=\dfrac{1}{2}+\dfrac{5}{6}-\dfrac{1}{2}-\dfrac{5}{6}+2022=2022\)
\(\dfrac{18}{45}\) + \(\dfrac{16}{12}\) + \(\dfrac{6}{30}\) - \(\dfrac{6}{9}\) - \(\dfrac{21}{35}\)
= \(\dfrac{2}{5}\) + \(\dfrac{4}{3}\) + \(\dfrac{1}{5}\) - \(\dfrac{2}{3}\) - \(\dfrac{3}{5}\)
= (\(\dfrac{2}{5}\) + \(\dfrac{1}{5}\) - \(\dfrac{3}{5}\)) + (\(\dfrac{4}{3}\) - \(\dfrac{2}{3}\))
= (\(\dfrac{3}{5}\) - \(\dfrac{3}{5}\)) + \(\dfrac{2}{3}\)
= 0 + \(\dfrac{2}{3}\)
= \(\dfrac{2}{3}\)
18454518 + 16121216 + 630306 - 6996 - 21353521
= 2552 + 4334 + 1551 - 2332 - 3553
= (2552 + 1551 - 3553) + (4334 - 2332)
= (3553 - 3553) + 2332
= 0 + 2332
= 2332