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9 tháng 4 2018

a) 2/7+-3/8+11/7+1/3+1/7+5/-8

=(2/7+11/7+1/7)+(3/8+-5/8)+1/3

=2+2+1/3

=4+1/3

=13/3

b) -3/8+12/25+5/-8+2/-5+13/25

=(-3/8+-5/8)+(12/25+13/25)+-2/5

=-1+1+-2/5

=0+-2/5

=-2/5

c)7/8+1/8*3/8+1/8*5/8

=7/8+1/8*(3/8+5/8)

=7/8+1/8*1

=7/8+1/8

=1

9 tháng 4 2018

a) 2/7+-3/8+11/7+1/3+1/7+5/-8

=(2/7+11/7+1/7)+(3/8+-5/8)+1/3

=2+2+1/3

=4+1/3

=13/3

b) -3/8+12/25+5/-8+2/-5+13/25

=(-3/8+-5/8)+(12/25+13/25)+-2/5

=-1+1+-2/5

=0+-2/5

=-2/5

c)7/8+1/8*3/8+1/8*5/8

=7/8+1/8*(3/8+5/8)

=7/8+1/8*1

=7/8+1/8

=1

3 tháng 5 2019

Giúp Mik ik mai nộp oy

1 tháng 4 2019

1. a) \(\frac{-2}{7}+\frac{15}{23}+\frac{\left(-15\right)}{17}+\frac{4}{19}+\frac{8}{23}\)

    \(=\left(\frac{-2}{7}+\frac{-5}{7}\right)+\left(\frac{15}{23}+\frac{8}{23}\right)+\frac{4}{19}\)

    \(=\left(-1\right)+1+\frac{4}{19}\)

    \(=0+\frac{4}{19}=\frac{4}{19}\)

b) \(\frac{7}{19}\cdot\frac{8}{11}+\frac{7}{19}\cdot\frac{3}{11}+\frac{12}{19}\)

   \(=\frac{7}{19}\cdot\left(\frac{8}{11}+\frac{3}{11}\right)+\frac{12}{19}\)

   \(=\frac{7}{19}\cdot1+\frac{12}{19}\)

   \(=\frac{7}{19}+\frac{12}{19}=\frac{19}{19}=1\)

1 tháng 4 2019

2. a) \(\frac{1}{3}+\frac{\left(-2\right)}{16}-\frac{7}{14}\)

\(=\frac{5}{24}-\frac{1}{2}\)

\(=-\frac{7}{24}\)

b) \(11\frac{3}{13}-2\frac{4}{7}+5\frac{3}{13}\)

\(=\left(11-2+5\right)+\frac{3}{13}-\frac{4}{7}+\frac{3}{13}\)

\(=14+\left(-\frac{10}{91}\right)\)

\(=-14\frac{10}{91}\)

c) \(0,7\cdot2\frac{2}{3}\cdot20\cdot0,375\cdot\frac{5}{28}\)

\(=\frac{7}{10}\cdot\frac{8}{3}\cdot20\cdot\frac{3}{8}\cdot\frac{5}{28}\)

\(=\left(\frac{7}{10}\cdot\frac{5}{28}\right)\cdot\left(\frac{8}{3}\cdot\frac{3}{8}\right)\cdot20\)

\(=\frac{1}{8}\cdot1\cdot20\)

\(=\frac{20}{8}=\frac{5}{2}\)

d) \(\frac{6}{7}+\frac{5}{7}:5-\frac{8}{9}\)

\(=\frac{6}{7}+\frac{1}{7}-\frac{8}{9}\)

\(=1-\frac{8}{9}\)

\(=\frac{1}{9}\)

~Học tốt~

15 tháng 8 2019

\(A=49\frac{8}{23}-\left(5\frac{7}{32}+14\frac{8}{23}\right)\)

\(A=49\frac{8}{23}-5\frac{7}{32}+14\frac{8}{23}\)

\(A= \left(49\frac{8}{23}-14\frac{8}{23}\right)-5\frac{7}{32}\)

\(A=\left[\left(49-14\right)-\left(\frac{8}{23}-\frac{8}{23}\right)\right]-5\frac{7}{32}\)

\(A=\left[35-0\right]-5\frac{7}{32}\)

\(A=35-5\frac{7}{32}\)

\(A=\frac{953}{32}\)

\(B=71\frac{38}{45}-\left(43\frac{38}{45}-1\frac{17}{57}\right)\)

\(B=71\frac{38}{45}-\frac{36377}{855}\)

\(B=\frac{1670}{57}\)

\(C=\left(19\frac{5}{8}:\frac{7}{12}-13\frac{1}{4}:\frac{7}{12}\right):\frac{4}{5}\)

\(C=\left[\left(19\frac{5}{8}-13\frac{1}{4}\right):\frac{7}{12}\right]:\frac{4}{5}\)

\(C=\left[\frac{51}{8}:\frac{7}{12}\right]:\frac{4}{5}\)

\(C=\frac{153}{14}:\frac{4}{5}\)

\(C=\frac{765}{56}\)

\(D=\left[\left(\frac{10}{15}-\frac{2}{3}\right):\frac{1}{7}\right]\cdot0,15-\frac{1}{4}\)

\(D=\left[0:\frac{1}{7}\right]\cdot\frac{3}{20}-\frac{1}{4}\)

\(D=0\cdot\frac{3}{20}-\frac{1}{4}\)

\(D=0-\frac{1}{4}\)

\(D=-\frac{1}{4}\)

\(E=\frac{13}{30}+\frac{28}{45}\cdot2\frac{1}{2}-\left[\left(\frac{1}{2}+\frac{1}{3}\right):\frac{53}{90}\right]:\frac{50}{53}\)

\(E=\frac{13}{30}+\frac{28}{45}\cdot\frac{5}{2}-\left[\frac{5}{6}:\frac{53}{90}\right]:\frac{50}{53}\)

\(E=\frac{13}{30}+\frac{28}{45}\cdot\frac{5}{2}-\frac{75}{53}:\frac{50}{53}\)

\(E=\frac{13}{30}+\frac{14}{9}-\frac{3}{2}\)

\(\)\(E=\frac{22}{45}\)

CHUC BAN HOC TOT >.<

6 tháng 6 2016

e) \(E=0,7.2\frac{2}{3}.20.0,375.\frac{5}{28}\)

        \(=\left(0,7.20\right)\left(2\frac{2}{3}.0,375\right)\frac{5}{28}\)

        \(=14.1.\frac{5}{28}\)

        \(=14.\frac{5}{28}\)

        \(=\frac{5}{2}\)

f) \(F=\left(9,75.21\frac{3}{7}+\frac{39}{4}.18\frac{4}{7}\right)\frac{15}{78}\)

       \(=\left(\frac{39}{4}.21\frac{3}{7}+\frac{39}{4}.18\frac{4}{7}\right)\frac{15}{78}\)

       \(=\frac{39}{4}\left(21\frac{3}{7}+18\frac{4}{7}\right)\frac{15}{78}\)

       \(=\frac{39}{4}.40.\frac{15}{78}\)

       \(=390.\frac{15}{78}\)

       \(=78\)

Chúc bạn học tốt môn Toán!!!

6 tháng 6 2016

Mình ko ghi đề đâu

\(A=49\frac{8}{23}-5\frac{7}{32}-14\frac{8}{23}=\left(49\frac{8}{23}-14\frac{8}{23}\right)-5\frac{7}{32}=35-5\frac{7}{32}=29\frac{25}{32}\)

\(B=71\frac{38}{45}-43\frac{8}{45}+1\frac{17}{57}=\left(71\frac{38}{45}-43\frac{8}{45}\right)+1\frac{17}{57}=28\frac{2}{3}+1\frac{17}{57}=29\frac{55}{57}\)

\(C=-\frac{3}{7}.\left(\frac{5}{9}+\frac{4}{9}\right)+2\frac{3}{7}=-\frac{3}{7}.1+2\frac{3}{7}=-\frac{3}{7}+2\frac{3}{7}=2\)