Question

Giúp em với ạ!!!

Thực hiện các phép tính:

a/ \(\dfrac{2}{3}\)+\(\dfrac{1}{5}\).\(\dfrac{10}{7}\)\(\)

b/ \(\dfrac{7}{12}\)-\(\dfrac{27}{7}\)\(\).\(\dfrac{1}{8}\)

c/ \(\dfrac{5}{9}\).\(\dfrac{7}{13}\)\(\)+\(\dfrac{5}{9}\).\(\dfrac{9}{13}\)-\(\dfrac{3}{13}\).\(\dfrac{5}{9}\)

Em cần ngay ạ!!!

Answer 1

\(\dfrac{2}{3}+\dfrac{1}{5}.\dfrac{10}{7}=\dfrac{2}{3}+\dfrac{10}{35}=\dfrac{70}{105}+\dfrac{30}{105}=\dfrac{100}{105}=\dfrac{50}{21}\)

Answer 2

a) Ta có: \(\dfrac{2}{3}+\dfrac{1}{5}\cdot\dfrac{10}{7}\)

\(=\dfrac{2}{3}+\dfrac{2}{7}\)

\(=\dfrac{14}{21}+\dfrac{6}{21}\)

\(=\dfrac{20}{21}\)

Answer 3

\(\dfrac{7}{12}-\dfrac{27}{7}.\dfrac{1}{8}=\dfrac{7}{12}-\dfrac{27}{56}=\dfrac{392}{672}-\dfrac{324}{672}=\dfrac{68}{672}=\dfrac{17}{168}\)

Answer 4

b) Ta có: \(\dfrac{7}{12}-\dfrac{27}{7}\cdot\dfrac{1}{8}\)

\(=\dfrac{7}{12}-\dfrac{27}{56}\)

\(=\dfrac{98}{168}-\dfrac{81}{168}\)

\(=\dfrac{17}{168}\)

Answer 5

c) Ta có: \(\dfrac{5}{9}\cdot\dfrac{7}{13}+\dfrac{5}{9}\cdot\dfrac{9}{13}-\dfrac{3}{13}\cdot\dfrac{5}{9}\)

\(=\dfrac{5}{9}\left(\dfrac{7}{13}+\dfrac{9}{13}-\dfrac{3}{13}\right)\)

\(=\dfrac{5}{9}\cdot1=\dfrac{5}{9}\)

Answer 6

\(\dfrac{5}{9}.\dfrac{7}{13}+\dfrac{5}{9}.\dfrac{9}{13}-\dfrac{3}{13}.\dfrac{5}{9}=\dfrac{35}{117}+\dfrac{5}{13}-\dfrac{5}{39}=\dfrac{5}{9}\)

Answer 7

\(\dfrac{5}{9}.\dfrac{7}{13}+\dfrac{5}{9}.\dfrac{9}{13}-\dfrac{3}{13}.\dfrac{5}{9}=\dfrac{5}{9}\left(\dfrac{7}{13}+\dfrac{9}{13}-\dfrac{3}{13}\right)=\dfrac{5}{9}.\dfrac{13}{13}=\dfrac{5}{9}\)

Answer 8

2/3+1/5x10/7=2/3+10/35=70/105+30/105=50/21

Answer 9

Giải:

a)2/3+1/5.10/7

=2/3+2/7

=20/21

b)7/12-27/7.1/8

=7/12-27/56

=17/168

c)5/9.7/13+5/9.9/13-3/13.5/9

=5/9.(7/13+9/13-3/13)

=5/9.1

Chúc bạn học tốt!

Answer 10

\(\dfrac{2}{3}\)+\(\dfrac{1}{5}\).\(\dfrac{10}{7}\)=\(\dfrac{2}{3}\)+\(\dfrac{10}{35}\)=\(\dfrac{70}{105}\)+\(\dfrac{30}{105}\)=\(\dfrac{100}{105}\)=\(\dfrac{50}{21}\)=\(\dfrac{2}{8}21\).