\(\dfrac{5}{15}+\dfrac{48}{16}=\dfrac{1}{3}+3=\dfrac{1}{3}+\dfrac{9}{3}=\dfrac{10}{3}\)

\(\dfrac{6}{9}:\dfrac{12}{36}=\dfrac{2}{3}:\dfrac{1}{3}=\dfrac{2}{3}\times\dfrac{3}{1}=\dfrac{6}{3}=2\)

\(\dfrac{4}{12}\times\dfrac{56}{14}=\dfrac{1}{3}\times4=\dfrac{4}{3}\)

a: 78/42-4/7=13/7-4/7=9/7

100/110-56/88=10/11-7/11=3/11

75/35-11/7+21/49=15/7-11/7+3/7=7/7=1

99/72-15/40-1212/1616=11/8-3/8-3/4=1-3/4=1/4

\(\frac{3}{9}\cdot\frac{5}{4}=\frac{1}{3}\cdot\frac{5}{4}\)

\(=\frac{1.5}{3.4}\)

\(=\frac{5}{12}\)

3/9=1/3

5/4=5/4(ko rút gọn đc)

3/9x5/4=5/12

NHỚ K CHO MK NHA

`42/48 = 7/8 , 8/32 = 1/4`

`7/8 + 1/4 = 9/8`

\(\dfrac{42}{48}\)=\(\dfrac{6}{7}\) và \(\dfrac{8}{32}\)=\(\dfrac{1}{4}\)

\(\frac{8}{15}+\frac{2}{3}=\frac{8}{15}+\frac{10}{15}=\frac{18}{15}=\frac{6}{5}\)

\(\frac{3}{7}+\frac{4}{8}=\frac{24}{56}+\frac{28}{56}=\frac{52}{56}=\frac{13}{14}\)

\(\frac{8}{15}+\frac{2}{3}=\frac{8}{15}+\frac{10}{15}=\frac{18}{15}=\frac{6}{5}\)

\(\frac{3}{7}+\frac{4}{8}=\frac{24}{56}+\frac{21}{56}=\frac{45}{56}\)

\(\frac{8}{15}+\frac{2}{3}=\frac{8}{15}+\frac{10}{15}=\frac{6}{5}\)

\(\frac{3}{7}+\frac{4}{8}=\frac{24}{56}+\frac{28}{56}=\frac{13}{14}\)

a 1,2

b 13/14

`8/56+3/21`

`=1/7+1/7`

`=2/7`

=1/7 + 1/7 =2/7