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(2/5-3/4)-2/5
-7/20-2/5
-3/4
-10/11.4/7+-10/7.3/7+21/11
-10/11.(4/7+3/7)+21/11
-10/11.1+21/11
-10/11+21/11
1
\(a,\left(\frac{2}{5}-\frac{3}{4}\right)-\frac{2}{5}\)
\(=\frac{2}{5}-\frac{3}{4}-\frac{2}{5}\)
\(=\frac{2}{5}-\frac{2}{5}-\frac{3}{4}\)
\(=0-\frac{3}{4}\)
\(=-\frac{3}{4}\)
\(b,\frac{-10}{11}.\frac{4}{7}+\frac{-10}{11}.\frac{3}{7}+1\frac{10}{11}\)
\(=\frac{-10}{11}.\left(\frac{4}{7}+\frac{3}{7}\right)+1\frac{10}{11}\)
\(=\frac{-10}{11}+1+\frac{10}{11}\)
\(=\left(\frac{-10}{11}+\frac{10}{11}\right)+1\)
\(=1\)
Học tốt
\(\frac{7}{4}\left(\frac{33}{12}+\frac{3333}{2020}+\frac{333333}{303030}+\frac{33333333}{42424242}\right)\)
=\(\frac{7}{4}\left(\frac{33}{12}+\frac{33}{20}+\frac{33}{30}+\frac{33}{42}\right)\)
=\(\frac{7}{4}.33\left(\frac{1}{3.4}+\frac{1}{4.5}+\frac{1}{5.6}+\frac{1}{6.7}\right)\)
=\(\frac{231}{4}\left(\frac{1}{3}-\frac{1}{4}+\frac{1}{4}-\frac{1}{5}+\frac{1}{5}-\frac{1}{6}+\frac{1}{6}-\frac{1}{7}\right)\)
=\(\frac{231}{4}\left(\frac{1}{3}-\frac{1}{7}\right)\)
=\(\frac{231}{4}.\frac{4}{21}\)
= 11
\(\dfrac{-7}{4}.\left(\dfrac{33}{12}+\dfrac{3333}{2020}+\dfrac{333333}{303030}+\dfrac{33333333}{42424242}\right)\)
\(=\dfrac{-7}{4}.\left(\dfrac{33}{12}.\dfrac{33.101}{20.101}.\dfrac{33.10101}{30.10101}.\dfrac{33.1010101}{42.1010101}\right)\)
\(=\dfrac{-7}{4}.\left(\dfrac{33}{12}.\dfrac{33}{20}.\dfrac{33}{30}.\dfrac{33}{42}\right)\)
\(=\dfrac{-7}{4}.33.\left(\dfrac{1}{12}+\dfrac{1}{20}+\dfrac{1}{30}+\dfrac{1}{42}\right)\)
\(=\dfrac{-7}{4}.33.\left(\dfrac{1}{3}-\dfrac{1}{4}+\dfrac{1}{4}-\dfrac{1}{5}+\dfrac{1}{5}-\dfrac{1}{6}+\dfrac{1}{6}-\dfrac{1}{7}\right)\)
\(=\dfrac{-7}{4}.33.\left(\dfrac{1}{3}-\dfrac{1}{7}\right)\)
\(=\dfrac{-7}{4}.33.\dfrac{4}{21}\)
\(=33.\dfrac{-1}{3}\)
\(=11\)
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