a) \(\dfrac{5}{6}-\dfrac{2}{14}\)

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

\(=\dfrac{35}{42}-\dfrac{6}{42}\)

\(=\dfrac{29}{42}\)

b) \(\dfrac{5}{20}-\dfrac{1}{6}\)

\(=\dfrac{1}{4}-\dfrac{1}{6}\)

\(=\dfrac{3}{12}-\dfrac{2}{12}\)

\(=\dfrac{1}{12}\)

c) \(\dfrac{5}{9}-\dfrac{3}{12}\)

\(=\dfrac{5}{9}-\dfrac{1}{4}\)

\(=\dfrac{20}{36}-\dfrac{9}{36}\)

\(=\dfrac{11}{36}\)

d) \(8-\dfrac{4}{6}\)

\(=\dfrac{48}{6}-\dfrac{4}{6}\)

\(=\dfrac{44}{6}=\dfrac{22}{3}\).

1.

a, Ta có 28=14⇒14+56=1312(Bn tự quy đồng lên nhé !)

b,Ta có1216=34⇒18+34=78(Bn tự quy đồng lên nhé !)

c,Ta có636=16⇒14+16=512(Bn tự quy đồng lên nhé !)

d,Ta có1218=23⇒23+14=1112(Bn tự quy đồng lên nhé !)

7.Phần này mk chỉ cho đáp án thuia.67     ;     

 b,420=15     ;         

c,615       ;            

d,129

ai giúp em với ;(9huhu k 2

a) 12/15 rút gọn cho 3 bằng 4/5          

b) 20/15 rút gọn cho 5 bằng 4/3

c)36/24 rút gon cho 6 bằng 6/4 lại rút gọn tiếp cho 2 bằng 3/2

d) 2/4 rút gọn cho 2 bằng 1/ 2

e) 6/8 rút gọn cho 2 bằng 3/4

g) 4/10 rút gọn cho 2 bằng 2/ 5 .

Đáp án là như vậy k cho mình nha !!!

ai giúp em đi.em k 2 cái lunnn

a: \(\dfrac{1}{8}+\dfrac{5}{8}=\dfrac{1+5}{8}=\dfrac{6}{8}=\dfrac{3}{4}\)

b: \(\dfrac{1}{15}+\dfrac{4}{15}=\dfrac{1+4}{15}=\dfrac{5}{15}=\dfrac{1}{3}\)

c: \(\dfrac{5}{9}+\dfrac{7}{9}=\dfrac{5+7}{9}=\dfrac{12}{9}=\dfrac{4}{3}\)

d: \(\dfrac{23}{100}+\dfrac{27}{100}=\dfrac{23+27}{100}=\dfrac{50}{100}=\dfrac{1}{2}\)

a) 18+58=1+58=68=3418+58=1+58=68=34

b) 115+415=1+415=515=13115+415=1+415=515=13

c) 59+79=5+79=129=4359+79=5+79=129=43

d) 23100+27100=23+27100=50100=12

a) 

\(\dfrac{6}{12}=\dfrac{6:6}{12:6}=\dfrac{1}{2}\)

\(\Rightarrow\dfrac{1}{2}=\dfrac{1\times2}{2\times2}=\dfrac{2}{4}\)

Mà \(\dfrac{2}{4}< \dfrac{3}{4}\)

Vậy \(\dfrac{6}{12}< \dfrac{3}{4}\).

b)

\(\dfrac{8}{10}=\dfrac{8:2}{10:2}=\dfrac{4}{5}\)

Mà \(\dfrac{2}{5}< \dfrac{4}{5}\)

Vậy \(\dfrac{2}{5}< \dfrac{8}{10}\).

c)

\(\dfrac{40}{35}=\dfrac{40:5}{35:5}=\dfrac{8}{7}\)

Mà \(\dfrac{8}{7}>\dfrac{6}{7}\)

Vậy \(\dfrac{40}{35}>\dfrac{6}{7}\).

d)

\(\dfrac{8}{16}=\dfrac{8:8}{16:8}=\dfrac{1}{2}\)

Mà \(\dfrac{1}{2}< \dfrac{5}{2}\)

Vậy \(\dfrac{8}{16}< \dfrac{5}{2}\).

12/18 + 12/42 = 2/3 + 2/7 = 14/21 + 6/21 = 20/21

1/2 + 2/4 + 3/6 + 4/8 + 5/10 + 6/12

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

= 1/2 x 6

=6/2

=3

Còn phần D thì sao😶

tra hieu gi ca

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

a) 4/5+3/15=4/5+1/5=1

b) 2/3+32/24=2/3+4/3=2

c)5/6+15/18=5/6+5/6=5/3

3.

a)8/15+2/3=18/15=6/5

b)3/7+4/8=52/56=13/14

Nhớ k cho mình đó !

Đã hứa thì phải làm

a)1/3

b)4/5

c)1

d)2 nha

a)=2/3-1/3= 1/3

b)=7/5-3/5= 4/5

c)=3/2-1/2= 2/2=1

d)=11/4-3/4= 8/4= 2

a) \(\frac{2}{3}-\frac{3}{9}=\frac{2}{3}-\frac{1}{3}=\frac{1}{3}\)

b) \(\frac{7}{5}-\frac{15}{25}=\frac{7}{5}-\frac{3}{5}=\frac{4}{5}\)

c) \(\frac{3}{2}-\frac{4}{8}=\frac{3}{2}-\frac{1}{2}=1\)

d) \(\frac{11}{4}-\frac{6}{8}=\frac{11}{4}-\frac{3}{4}=2\)