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3/7x3/13+3/7:13/10+6/14
=3/7x3/13+3/7x10/13+6/14
=3/7x(3/13+10/13)+6/14
=3/7x1+6/14
=3/7+6/14
=3/7+3/7
=6/7
Đề:...........
= 3/7 x 3/13 + 3/7 x 10/13 + 3/7
= 3/7 x (3/13 + 10/13 + 1)
= 3/7 x ( 1 + 1 )
= 3/7 x 2
= 6/7
a) 563 x 23 + 23 x 28 - 23
= 23 x (563 + 28 - 1)
= 23 x 600
= 19200
b) \(\frac{7}{11}+\frac{3}{4}+\frac{4}{11}+\frac{1}{4}-1\frac{2}{5}=\left(\frac{7}{11}+\frac{4}{11}\right)+\left(\frac{3}{4}+\frac{1}{4}\right)-\frac{7}{5}=2-\frac{7}{5}=\frac{3}{5}\)
c) \(\left(1-\frac{1}{2}\right)\times\left(1-\frac{1}{3}\right)\times\left(1-\frac{1}{4}\right)\times...\times\left(1-\frac{1}{10}\right)=\frac{1}{2}\times\frac{2}{3}\times\frac{3}{4}\times....\times\frac{9}{10}\)
\(=\frac{1\times2\times3\times...\times9}{2\times3\times4\times...\times10}=\frac{1}{10}\)
d) \(\frac{2}{7}\times\frac{3}{9}+\frac{2}{7}\times\frac{2}{3}=\frac{2}{7}\times\left(\frac{3}{9}+\frac{2}{3}\right)=\frac{2}{7}\times1=\frac{2}{7}\)
a ) \(563\cdot23+23\cdot28-23\)
\(=23\cdot\left(563+28-1\right)\)
\(=23\cdot600\)
\(=19200\)
b ) \(\frac{7}{11}+\frac{3}{4}+\frac{4}{11}+\frac{1}{4}-1\frac{2}{5}=\left(\frac{7}{11}+\frac{4}{11}\right)+\left(\frac{3}{4}+\frac{1}{4}\right)-\frac{7}{5}=2-\frac{7}{5}=\frac{3}{5}\)
c ) \(\left(1-\frac{1}{2}\right)\cdot\left(1-\frac{1}{3}\right)\cdot\left(1-\frac{1}{4}\right)\cdot...\cdot\left(1-\frac{1}{10}\right)=\frac{1}{2}\cdot\frac{2}{3}\cdot\frac{3}{4}\cdot...\cdot\frac{9}{10}\)
\(=\frac{1\cdot2\cdot3\cdot...\cdot9}{2\cdot3\cdot4\cdot...\cdot10}=\frac{1}{10}\)
d ) \(\frac{2}{7}\cdot\frac{3}{9}+\frac{2}{7}\cdot\frac{2}{3}=\frac{2}{7}\cdot\left(\frac{3}{9}+\frac{2}{3}\right)=\frac{2}{7}\cdot1=\frac{2}{7}\)
\(6\dfrac{1}{7}\times1\dfrac{6}{7}\)
\(=\dfrac{43}{7}\times\dfrac{13}{7}\)
\(=\dfrac{559}{49}\)
#Toru
\(6\dfrac{1}{7}\times1\dfrac{6}{7}=\dfrac{43}{7}\times\dfrac{13}{7}=\dfrac{559}{49}\)
a)\(\frac{4}{5}-\frac{1}{4}+\frac{3}{10}\)
\(=\frac{16}{20}-\frac{5}{20}+\frac{6}{20}\)
\(=\frac{17}{20}\)
b) \(\frac{2}{5}:\left(1-\frac{1}{10}\right)\)
\(=\frac{2}{5}:\frac{9}{10}\)
\(=\frac{4}{9}\)
c)\(\frac{7}{8}\times\frac{4}{9}+\frac{1}{14}:\frac{5}{14}\)
\(=\frac{7}{18}+\frac{1}{5}\)
\(=\frac{53}{90}\)
d)\(\frac{2}{7}\times\frac{3}{11}+\frac{2}{7}\times\frac{8}{11}\)
\(=\frac{2}{7}\times\left(\frac{3}{11}+\frac{8}{11}\right)\)
\(=\frac{2}{7}\times1=\frac{2}{7}\)
e) \(12+\left(16-11\right)\times4\)
\(=12+20=32\)
f)\(2\frac{3}{7}+1\frac{4}{7}\)
\(=\frac{17}{7}+\frac{11}{7}\)
\(=4\)
g)\(\frac{2}{3}\times\frac{4}{5}+\frac{1}{5}:\frac{9}{11}\)
\(=\frac{8}{15}+\frac{11}{45}\)
\(=\frac{7}{9}\)
h)\(\left(6,2:2+3,7\right):0,2\)
\(=\left(3,1+3,7\right):0,2\)
\(=6,8:0,2=34\)
#H
a, \(\frac{1}{2}x\frac{2}{7}+\frac{3}{7}:2+\frac{1}{2}:\frac{7}{2}\)
= \(\frac{1}{2}x\frac{2}{7}+\frac{3}{7}x\frac{1}{2}+\frac{1}{2}x\frac{2}{7}\)
= \(\frac{1}{2}x\left(\frac{2}{7}+\frac{3}{7}+\frac{2}{7}\right)\)
= \(\frac{1}{2}x1\)
= \(\frac{1}{2}\)
\(a,\frac{1}{2}x\frac{2}{7}+\frac{3}{7}:2+\frac{1}{2}:\frac{7}{2}\)
\(=\frac{1}{2}x\frac{2}{7}+\frac{3}{7}x\frac{1}{2}+\frac{1}{2}x\frac{2}{7}\)
\(=\frac{1}{2}x\left(\frac{2}{7}+\frac{3}{7}+\frac{2}{7}\right)\)
\(=\frac{1}{2}x1\)
\(=\frac{1}{2}\)
\(b,\frac{3}{7}x\frac{3}{5}+\frac{3}{5}:7+\frac{3}{7}:\frac{5}{3}\)
\(=\frac{3}{7}x\frac{3}{5}+\frac{3}{5}x\frac{1}{7}+\frac{3}{7}x\frac{3}{5}\)
\(=\frac{3}{5}x\left(\frac{3}{7}+\frac{1}{7}+\frac{3}{7}\right)\)
\(=\frac{3}{5}x1\)
\(=\frac{3}{5}\)
\(\dfrac{2}{5}+\dfrac{3}{7}\)=\(\dfrac{14}{35}\)+\(\dfrac{15}{35}\)=\(\dfrac{29}{35}\)
16/49