4/9-5/18 = 8/18 - 5/18 = 3/18 = 1/6

3/5x5/7 = 3/7

4/7:2/7 = 4/7 x 7/2 = 2

4/9-5/18= 8/18 - 5/18 = 3/18 = 1/6

 3/5x5/7=15/35 = 3/7    

4/7:2/7=4/7 x 7/2 = 4/2 = 2

\(\frac{7}{9}\times\frac{3}{5}+\frac{3}{5}\times\frac{5}{6}+\frac{3}{5}\times1\)

\(=\frac{3}{5}\times\left(\frac{7}{9}+\frac{5}{6}+1\right)\)

\(=\frac{3}{5}\times\frac{47}{18}\)

\(=\frac{47}{30}\)

 #hoktot<3# 

a) = 29/5

b) = 1/10

c) = 1/2

d) ?

a) \(\dfrac{12}{15}+5=\dfrac{4}{5}+5=\dfrac{4}{5}+\dfrac{25}{5}=\dfrac{29}{5}\)

b) \(\dfrac{7}{10}-\dfrac{6}{10}=\dfrac{1}{10}\)

c) \(\dfrac{3}{5}x\dfrac{5}{6}=\dfrac{15}{30}=\dfrac{1}{2}\)

d) lỗi 

a) \(\dfrac{12}{15}+5=\dfrac{4}{5}+5=\dfrac{4}{5}+\dfrac{5}{1}=\dfrac{4}{5}+\dfrac{25}{5}=\dfrac{29}{5}\)

b) \(\dfrac{7}{10}-\dfrac{3}{5}=\dfrac{7}{10}-\dfrac{6}{10}=\dfrac{1}{10}\)

c) \(\dfrac{3}{5}\times\dfrac{5}{6}=\dfrac{3\times5}{5\times6}=\dfrac{15}{30}=\dfrac{1}{2}\)

d) Thiếu số

\(a,\dfrac{7}{15}+\dfrac{4}{5}=\dfrac{7+4\times3}{15}=\dfrac{19}{15}\\ b,\dfrac{2}{3}-\dfrac{3}{8}=\dfrac{2\times8-3\times3}{24}=\dfrac{7}{24}\\ c,\dfrac{4}{5}\times\dfrac{5}{8}=\dfrac{1\times1}{2\times1}=\dfrac{1}{2}\\ d,\dfrac{1}{2}:\dfrac{2}{5}=\dfrac{1}{2}\times\dfrac{5}{2}=\dfrac{5}{4}\)

nhanh lên giúp mình với

a) \(\dfrac{7}{15}+\dfrac{4}{5}\)

\(=\dfrac{7}{15}+\dfrac{12}{15}\)

\(=\dfrac{19}{15}\)

b) \(\dfrac{2}{3}-\dfrac{3}{8}\)

\(=\dfrac{16}{24}-\dfrac{9}{24}\)

\(=\dfrac{7}{24}\)

c) \(\dfrac{4}{5}\times\dfrac{5}{8}\)

\(=\dfrac{4\times5}{5\times8}\)

\(=\dfrac{4}{8}\)

\(=\dfrac{1}{2}\)

d) \(\dfrac{1}{2}:\dfrac{2}{5}\)

\(=\dfrac{1}{2}\times\dfrac{5}{2}\)

\(=\dfrac{1\times5}{2\times2}\)

\(=\dfrac{5}{4}\)

a) \(\dfrac{2}{5}\cdot\dfrac{1}{7}+\dfrac{2}{5}\cdot\dfrac{5}{7}+\dfrac{2}{5}\)

\(=\dfrac{2}{5}\left(\dfrac{1}{7}+\dfrac{5}{7}+1\right)\)

\(=\dfrac{2}{5}\cdot\dfrac{13}{7}=\dfrac{26}{35}\)

b) \(\dfrac{1}{5}+\dfrac{2}{8}+\dfrac{4}{5}+\dfrac{7}{8}-\dfrac{1}{8}\)

\(=\left(\dfrac{1}{5}+\dfrac{4}{5}\right)+\left(\dfrac{2}{8}+\dfrac{7}{8}-\dfrac{1}{8}\right)\)

\(=1+1=2\)

c)\(\dfrac{24}{36}\cdot\dfrac{10}{12}\cdot36\)

\(=\dfrac{24\cdot10\cdot36}{36\cdot12}=\dfrac{12\cdot2\cdot10\cdot36}{12\cdot36}\)

\(=2\cdot10=20\)

a. 1/3 + 1/4 - 1/6

= 7/12 - 1/6

= 5/12

b. 2/5 x 5/7 : 3/4

= 2/7 : 3/4

= 8/21

5x5 - 5x5 = 25 - 25 = 0

              Đáp số : 0 nhé bạn

zero nak! ~ mk đg nhớ 1 ng......ai đồng cảm thì kết bạn nhe!

0 nhé bạn

5 + 5 x 5 - 5 + 5 x 5 : 5 

= 5 + 25 - 5 + 5

= 30

= 5 + 25 - 5 + 25 : 5

= 5 + 25 - 5 + 5

= 30 - 5 + 5

= 25 + 5

= 30

5+5*5-5+5*5:5

=5+25-5+5

=30

\(\frac{3}{4}\cdot\frac{8}{5}\cdot\frac{5}{9}=\frac{2}{3}\)

\(\frac{3}{7}:\frac{3}{14}:\frac{1}{2}=4\)

cậu ghi lòi  giải ra được không

a) \(\frac{3}{4}x\frac{8}{5}x\frac{5}{9}=\frac{3x8x5}{4x5x9}=\frac{120}{180}=\frac{2}{3}\)

b) \(\frac{6}{7}:\frac{3}{14}:\frac{1}{2}=\frac{6}{7}x\frac{14}{3}x\frac{1}{2}=\frac{84}{42}=2\)