\(\frac{3}{8}+\frac{15}{32}=\frac{12}{32}+\frac{15}{32}=\frac{27}{32}\)

\(\frac{8}{9}-\frac{5}{36}=\frac{32}{36}-\frac{5}{36}=\frac{27}{36}=\frac{3}{4}\)

\(\frac{15}{6}-\frac{7}{4}+2=\frac{30}{12}-\frac{28}{12}+\frac{24}{12}=\frac{26}{12}=\frac{13}{6}\)

\(3-\left(\frac{3}{4}+\frac{5}{12}\right)=3-\left(\frac{9}{12}+\frac{5}{12}\right)=3-\frac{14}{12}=3-\frac{7}{6}=\frac{18}{6}-\frac{7}{6}=\frac{11}{6}\)

a)1

b)2

c)5/3

k mik nhé bn.chúc bn học tốt

a)1

b)2

c)5/3

a)\(\dfrac{5}{7}+\dfrac{4}{9}=\dfrac{45}{63}+\dfrac{28}{63}=\dfrac{73}{63}\) ; \(\dfrac{9}{11}+\dfrac{3}{8}=\dfrac{72}{88}+\dfrac{33}{88}=\dfrac{105}{88}\)

\(\dfrac{4}{5}-\dfrac{2}{3}=\dfrac{12}{15}-\dfrac{10}{15}=\dfrac{2}{15}\); \(\dfrac{16}{25}-\dfrac{2}{5}=\dfrac{16}{25}-\dfrac{10}{25}=\dfrac{6}{25}\)

b)\(5+\dfrac{3}{5}=\dfrac{25}{5}+\dfrac{3}{5}=\dfrac{28}{5};10-\dfrac{9}{16}=\dfrac{160}{16}-\dfrac{9}{16}=\dfrac{151}{16}\)

\(\dfrac{2}{3}-\left(\dfrac{1}{6}+\dfrac{1}{8}\right)=\dfrac{2}{3}-\left(\dfrac{8}{48}+\dfrac{6}{48}\right)=\dfrac{2}{3}-\dfrac{14}{48}=\dfrac{32}{48}-\dfrac{14}{48}=\dfrac{3}{8}\)

4/5 + 3/15 = 1

2/3 + 32/24 = 2

5/6 + 15/18 = 5/3

k nhé:))

\(\frac{4}{5}+\frac{3}{15}=\frac{4}{5}+\frac{1}{5}=\frac{4+1}{5}=\frac{5}{5}=1\)

\(\frac{2}{3}+\frac{32}{24}=\frac{2}{3}+\frac{4}{3}=\frac{2+4}{3}=\frac{6}{3}=2\)

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

                 HT

mn ơi e vít nhầm là tính rồi rút gọn mn sửa lại là rút gọn rùi tính

`3/7 + 4/5 + 4/7`

`= (3/7 +4/7)+4/5`

`= 7/7 +4/5`

`= 1 + 4/5`

`= 5/5 +4/5`

`=9/5`

`------`

`6/11 + 2/15 + 5/11`

`=(6/11 + 5/11)+2/15`

`= 1 + 2/15`

`= 15/15 +2/15`

`= 17/15`

`-----`

`4/9 + 2/5 + 15/27`

`= (4/9 + 15/27 )+2/5`

`= 1+2/5`

`=5/5 +2/5`

`=7/5`

`-----`

`6/13 + 9/32 + 21/26`

`= (6/13 + 21/26)+9/32`

`= ( 12/26 + 21/26)+9/32`

`= 33/26 +9/32`

`=645/416`

1, Rút gọn rồi tính 

a) \(\frac{4}{5}+\frac{3}{15}\)

= \(\frac{4}{5}+\frac{1}{5}\)

= \(\frac{5}{5}\)

= \(1\)

b) \(\frac{2}{3}+\frac{32}{24}\)

= \(\frac{2}{3}+\frac{4}{3}\)

= \(\frac{6}{3}\)

= \(2\)

c) \(\frac{5}{6}+\frac{15}{18}\)

= \(\frac{5}{6}+\frac{5}{6}\)

= \(\frac{10}{6}\)

= \(\frac{5}{3}\)

2, Tính rồi rút gọn 

a) \(\frac{8}{15}+\frac{2}{3}\)

= \(\frac{8}{15}+\frac{10}{15}\)

= \(\frac{18}{15}\)

= \(\frac{6}{5}\)

b) \(\frac{3}{7}+\frac{4}{8}\)

= \(\frac{24}{56}+\frac{28}{56}\)

= \(\frac{52}{56}\)

= \(\frac{13}{14}\)

Đáp án:

a) 1

b) 2

c) 5/3

Bài 3.Tính rồi rút gọn

a)6/5

b) 13/14

tất cả ý đều đúng nhé