\(\frac{10}{7}\cdot\frac{2}{3}+\frac{5}{6}:\frac{3}{10}-\frac{2}{3}\cdot\frac{3}{7}\)

\(=\left(\frac{10}{7}\cdot\frac{2}{3}-\frac{2}{3}\cdot\frac{3}{7}\right)+\frac{5}{6}\cdot\frac{10}{3}\)

\(=\frac{2}{3}\left(\frac{10}{7}-\frac{3}{7}\right)+\frac{5\cdot10}{6\cdot3}\)

\(=\frac{2}{3}\cdot1+\frac{25}{9}\)

\(=\frac{2}{3}+\frac{25}{9}\)

\(=\frac{31}{9}\)

Tính bằng các thuận tiện nhất: 10/7 x 2/3 + 6/5 : 3/10 - 2/3 x 3/7

trả lời:

10/7 x 2/3 + 6/5 : 3/10 - 2/3 x 3/7=10/7 x 2/3 + 6/5. 10/3 - 2/3 x 3/7=10/7 x 2/3 + 2/3.2- 2/3 x 3/7

=2/3.(10/7+2-3/7)=2/3.3=2

   10/7 x 2/3 + 6/5 : 3/10 - 2/3 x 3/7
= 10/7 x 2/3 + 6/5 x 10/3 - 2/3 x 3/7
= 10/7 x 2/3 + 6/5 x 5 x 2/3 - 2/3 x 3/7
= 10/7 x 2/3 + 6 x 2/3 - 2/3 x 3/7
= 2/3 x (6 + 10/7 - 3/7)
= 2/3 x (6 + 1)
= 2/3 x 7
= 14/3
CHúc bạn học tốt
 

3.12:0.25+12.48*3-3.12*6

=3.12*4+3.12*12-3.12*6

=3.12*(4+12-6)

=3.12*10

=31.2

= 3,12 x 4 + 3,12 x 4 x 3 - 3,12 x 6

= 3,12 x 4 +3,12 x 12 - 3,12 x 6

= 3,12 x ( 4 + 12 - 6 )

= 3,12 x 10

= 31,2

    3,12 : 0,25 + 12,48 x 3 - 3,12 x 6

=  3,12 x 4 + 3,12 x ( 4 x 3 ) - 3,12 x 6

= 3,12  x 4 + 3,12 x 12 - 3,12 x 6

= 3,12 x ( 4 + 12 - 6 )

= 3,12 x         10

= 31,2

3,12 : 0,25 + 12,48 x 3 - 3,12 x 6

=3,12 : 1/4 + 3,12 x 4 x 3 - 3,12 x 6

=3,12 x 4 + 3,12 x 12 - 3,12 x 6

=3,12 x (4 + 12 - 6)

=3,12 x 10

=31,2

6/7 * 5/8*7/3*7/6*8/5

= 6*5*7*7*8 /7*8*3*6*5

=1*1*7*1*1/1*1*3*1*1

= 7/3 

=7/10(3+5+2)

=7/10*10

=7

3 x 7/10 + 7/10 x 5 + 2 x 7/10

= 7/10 x (3 + 5 + 2)

= 7/10 x 10

= 7

\(5\dfrac{3}{4}:3+2\dfrac{1}{4}\times\dfrac{1}{3}-\dfrac{1}{8}=\left(5\dfrac{3}{4}+2\dfrac{1}{4}\right)\times\dfrac{1}{3}-\dfrac{1}{8}\\ =8\times\dfrac{1}{3}-\dfrac{1}{8}=\dfrac{8}{3}-\dfrac{1}{8}=\dfrac{61}{24}\\ ----\\ \dfrac{3}{5}:\dfrac{5}{6}:\dfrac{6}{7}:\dfrac{7}{8}+\dfrac{2}{5}+\dfrac{23}{35}\\ =\dfrac{3}{5}\times\dfrac{6}{5}\times\dfrac{7}{6}\times\dfrac{8}{7}+\dfrac{2}{5}+\dfrac{23}{35}=\dfrac{18}{25}\times\dfrac{4}{3}+\dfrac{2}{5}+\dfrac{23}{35}=\dfrac{353}{175}\)

a)=2

b)=1/3