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=> 20 x ( 10 + 9 + 11 ) + 10 x ( 2 + 3 + 4 + 1 )
=> 20 x 30 + 10 x 10
=> 600 + 100
=> 700
3 x 7/10 + 7/10 x 5 +2 x 7/10
=7/10 x (3 + 5 + 2)
= 7/10 x 10
= 70/10=7
hok tốt nha
\(3\times\frac{7}{10}+\frac{7}{10}\times5+2\times\frac{7}{10}\)
\(=\frac{7}{10}\times\left(3+5+2\right)\)
\(=\frac{7}{10}\times10=\frac{7\times10}{10}=7\)
6 x5/3=10 7:8/4+1/3=23/6 2x5/8-1/2=3/4 3/7:5/6x1/4=9/70
a) C1 : 2/5 x 3/7 + 2/7 x 4/7
= 2/5 x (3/7 + 4/7)
= 2/5 x 1
= 2/5
C2 : 2/5 x 3/7 + 2/5 x 4/7
= 6/35 + 8/35
= 2/5
b) (2/3 - 4/7) x 5/5
= 2/21 x 5/5
= 2/21
C2 : (2/3 - 4/7) x 5/5
= 2/3 x 1 - 4/7 x 1
= 2/3 - 4/7
= 2/21
c) 3/4 x 2/5 - 3/4 x 2/7
= 3/4 x (2/5 - 2/7)
= 3/4 x 4/35
= 3/35
C2 : 3/4 x 2/5 - 3/4 x 2/7
= 3/10 - 3/14
= 3/35
a,
Cách 1
\(\frac{2}{5}\times\frac{3}{7}+\frac{2}{5}\times\frac{4}{7}\)
\(=\frac{6}{35}+\frac{8}{35}\)
\(=\frac{2}{5}\)
Cách 2 :
\(\frac{2}{5}\times\frac{3}{7}+\frac{2}{5}\times\frac{4}{7}\)
\(=\frac{2}{5}\times\left(\frac{3}{7}+\frac{4}{7}\right)\)
\(=\frac{2}{5}\times1\)
\(=\frac{2}{5}\)
b,
Cách 1 :
\(\left(\frac{2}{3}-\frac{4}{7}\right)\times\frac{5}{5}\)
\(=\frac{2}{21}\times1\)
\(=\frac{2}{21}\)
Cách 2 :
\(\left(\frac{2}{3}-\frac{4}{7}\right)\times\frac{5}{5}\)
\(=\frac{2}{3}\times\frac{5}{5}-\frac{4}{7}\times\frac{5}{5}\)
\(=\frac{2}{3}-\frac{4}{7}\)
\(=\frac{2}{21}\)
c,
Cách 1 :
\(\frac{3}{4}\times\frac{2}{5}-\frac{3}{4}\times\frac{2}{7}\)
\(=\frac{3}{10}-\frac{3}{14}\)
\(=\frac{3}{35}\)
Cách 2 :
\(\frac{3}{4}\times\frac{2}{5}-\frac{3}{4}\times\frac{2}{7}\)
\(=\frac{3}{4}\times\left(\frac{2}{5}-\frac{2}{7}\right)\)
\(=\frac{3}{4}\times\frac{4}{35}\)
\(=\frac{3}{35}\)
Mk nhanh nhất đó
Đúng 100%
Tk mk mk tk lại
Cảm ơn bạn nhiều
Thank you very much
( ^ _ ^ )
a. \(\left(2-\frac{2}{17}\right)\times\frac{51}{64}\)
\(=\frac{22}{17}\times\frac{51}{64}\)
\(=\frac{22\times51}{17\times64}=\frac{1122}{1088}=\frac{561}{544}\)
b. \(\left(\frac{2}{5}+\frac{5}{7}\right)\times\frac{5}{13}\)
\(=\frac{39}{35}\times\frac{5}{13}\)
\(=\frac{3}{7}\)
c. \(\frac{13}{18}\div\left(\frac{7}{12}-\frac{4}{9}\right)\)
\(=\frac{13}{18}\div\frac{28}{27}\)
\(=\frac{13}{18}\times\frac{27}{28}=\frac{39}{56}\)
#z
\(\left(2-\frac{2}{17}\right)\times\frac{51}{64}\)
\(=\frac{32}{17}\times\frac{51}{64}\)
\(=\frac{1632}{1088}=\frac{3}{2}\)
\(\left(\frac{2}{5}+\frac{5}{7}\right)\times\frac{5}{13}\)
\(=\left(\frac{14}{35}+\frac{25}{35}\right)\times\frac{5}{13}\)
\(=\frac{39}{35}\times\frac{5}{13}\)
\(=\frac{195}{455}=\frac{3}{7}\)
\(\frac{13}{18}:\left(\frac{7}{12}-\frac{4}{9}\right)\)
\(=\frac{13}{18}:\left(\frac{63}{108}-\frac{48}{108}\right)\)
\(=\frac{13}{18}:\frac{5}{36}\)
\(=\frac{13}{18}\times\frac{36}{5}\)
\(=\frac{468}{90}=\frac{26}{5}\)
\(=\dfrac{7}{10}\times\left(3+5+2\right)=\dfrac{7}{10}\times10=7\)
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