12/15 =48/100

4/7 = 28/49

45/81 =5/9

2/3 = 36/54

k mk nha

 k mk đi, làm ơnnnnn

\(\frac{2}{3}=\frac{36}{54}\)

\(\frac{4}{7}=\frac{28}{49}\)

\(\frac{48}{100}=\frac{12}{25}\)

\(\frac{45}{81}=\frac{5}{9}\)

Thanks CTV nhé !!

\(\dfrac{5}{6}=\dfrac{15}{18}\)

\(\dfrac{9}{11}=\dfrac{27}{33}\)

\(\dfrac{5}{8}=\dfrac{25}{40}\)

\(\dfrac{12}{16}=\dfrac{36}{48}\)

\(\dfrac{8}{12}=\dfrac{40}{60}\)

5/6= 27/33

12/16= 36/48

8/12= 40/60

25/40= 5/8

15/18= 5/6

300

465 

Tham khảo:

\(\dfrac{4}{7}-\dfrac{1}{3}< \dfrac{1}{2}-\dfrac{2}{9}\)

\(\dfrac{125}{100}-\dfrac{48}{64}< \dfrac{6}{7}-\dfrac{14}{28}\)

\(\dfrac{7}{5}-\dfrac{22}{25}=\dfrac{1}{5}+\dfrac{4}{10}\)\(\dfrac{45}{75}+\dfrac{22}{33}>\dfrac{4}{5}+\dfrac{4}{6}\)

a) 3/7 + 4/9 + 4/7 + 5/9

= ( 3/7 + 4/7 ) + ( 4/9 + 5/9 )

= 7/7 + 9/9

= 1  + 1 

= 2

b)1/5 + 4/10 + 9/15 + 16/20 + 25/25 + 36/30 + 49/35 + 64/40 + 81/45

= 1/5 + 2/5 + 3/5 + 4/5 + 5/5 + 6/5 + 7/5 + 8/5 + 9/5

= ( 1/5 + 9/5 ) + ( 2/5 + 8/5 ) + (7/5 + 3/5 ) + ( 4/5 + 6/5  ) + 5/5

= 2 + 2 + 2 + 2 + 1

= 2  x 4 + 1

= 8  +1 

= 9

c)  1/8 + 1/12 + 3/8 + 5/12

= ( 1/8 + 3/8 ) + ( 1/12 + 5/12)

= 4/8 + 6/12

= 1/2 + 1/2

= 2/4 = 1/2

mỏi tay rồi

d; (1 - \(\dfrac{1}{2}\)) x (1 - \(\dfrac{1}{3}\)) x (1 - \(\dfrac{1}{4}\)) x ... x ( 1 - \(\dfrac{1}{100}\))

 = \(\dfrac{1}{2}\) x \(\dfrac{2}{3}\)  x \(\dfrac{3}{4}\) x \(\dfrac{3}{4}\) x ... x \(\dfrac{99}{100}\)

= \(\dfrac{1}{100}\)