(\(\frac{3}{8}\)-\(\frac{1}{5}\)-\(\frac{1}{3}\))+(\(\frac{5}{8}\)-\(1\frac{3}{7}\)-\(\frac{4}{7}\))+\(\frac{1}{3}\)
K
Khách
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Những câu hỏi liên quan
2 tháng 8 2015
\(=\frac{5\left(\frac{1}{3}+\frac{1}{8}-\frac{1}{7}\right)}{-4\left(\frac{1}{3}+\frac{1}{8}-\frac{1}{7}\right)}:\frac{2\left(\frac{1}{3}-\frac{1}{12}+\frac{3}{7}\right)}{ }\)
MÃu thứ hai sao ý
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
S
12 tháng 10 2018
3/8-1/5-1/3+5/8-10/7-4/7+1/3
=(3/8+5/8)-(1/3-1/3)-1/5-(10/7+4/7)
=1-0-1/5-2
=4/5-2
=-6/5
12 tháng 10 2018
\(\left(\frac{3}{8}-\frac{1}{5}-\frac{1}{3}\right)+\left(\frac{5}{8}-\frac{10}{7}-\frac{4}{7}\right)+\frac{1}{3}\)
\(=\frac{3}{8}-\frac{1}{5}-\frac{1}{3}+\frac{5}{8}-\frac{10}{7}-\frac{4}{7}+\frac{1}{3}\)
\(=\left(\frac{3}{8}+\frac{5}{8}\right)+\left(\frac{-1}{3}+\frac{1}{3}\right)-\left(\frac{10}{7}+\frac{4}{7}\right)-\frac{1}{5}\)
\(=1+0-2-\frac{1}{5}\)
\(=\left(-1\right)-\frac{1}{5}\)
\(=\frac{-6}{5}\)
NT
27 tháng 2 2018
\(A=\frac{1}{2}.\frac{1}{3}+\frac{1}{3}.\frac{1}{4}+\frac{1}{4}.\frac{1}{5}+\frac{1}{5}.\frac{1}{6}+\frac{1}{6}.\frac{1}{7}+\frac{1}{7}.\frac{1}{8}+\frac{1}{8}.\frac{1}{9}\)
\(A=\frac{1}{2.3}+\frac{1}{3.4}+\frac{1}{4.5}+\frac{1}{5.6}+\frac{1}{6.7}+\frac{1}{7.8}+\frac{1}{8.9}\)
\(A=\frac{3-2}{2.3}+\frac{4-3}{3.4}+\frac{5-4}{4.5}+\frac{6-5}{5.6}+\frac{7-6}{6.7}+\frac{8-7}{7.8}+\frac{9-8}{8.9}\)
\(A=\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+\frac{1}{4}-\frac{1}{5}+\frac{1}{5}-\frac{1}{6}+\frac{1}{6}-\frac{1}{7}+\frac{1}{7}-\frac{1}{8}+\frac{1}{8}-\frac{1}{9}\)
\(A=\frac{1}{2}-\frac{1}{9}\)
\(A=\frac{7}{18}\)
Vậy \(A=\frac{7}{18}\)
27 tháng 2 2018
A = 1/2.3 + 1/3.4 + ..... +1/8.9
= 1/2 - 1/3 + 1/3 - 1/4 + ........ + 1/8 - 1/9
= 1/2 - 1/9
= 7/18
Tk mk nha
LB
1 tháng 4 2017
\(S=1-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+\frac{1}{4}-\frac{1}{5}+\frac{1}{5}-\frac{1}{6}+\frac{1}{6}-\frac{1}{7}+\frac{1}{7}-\frac{1}{8}+\frac{1}{8}-\frac{1}{9}\)
\(S=1-\frac{1}{9}=\frac{8}{9}\)
\(\left(\frac{3}{8}-\frac{1}{5}-\frac{1}{3}\right)+\left(\frac{5}{8}-1\frac{3}{7}-\frac{4}{7}\right)+\frac{1}{3}\)
\(=\frac{3}{8}-\frac{1}{5}-\frac{1}{3}+\frac{5}{8}-1\frac{3}{7}-\frac{4}{7}+\frac{1}{3}\)
\(=\frac{3}{8}-\frac{1}{5}-\frac{1}{3}+\frac{5}{8}-\frac{10}{7}-\frac{4}{7}+\frac{1}{3}\)
\(=\left(\frac{3}{8}+\frac{5}{8}\right)+\left(\frac{1}{3}-\frac{1}{3}\right)-\left(\frac{10}{7}+\frac{4}{7}\right)-\frac{1}{5}\)
\(=\frac{8}{8}+0-\frac{14}{7}-\frac{1}{5}\)
\(=1+0-2-\frac{1}{5}\)
\(=-1-\frac{1}{5}\)
\(=-1\frac{1}{5}\)