=1/10+1/10+3/10+4/10+5/10+6/10+7/10+8/10+9/10

=1/10+45/10

=46/10=23/5

bạn dùng cách nào mà viết được phân số bạn đang viết vậy

\(\frac{7}{8}\)x \(\frac{8}{9}\)x \(\frac{9}{10}\)

= \(\frac{7}{9}\)x  \(\frac{9}{10}\)

= \(\frac{7}{10}\)

1 x \(\frac{2}{3}\): \(\frac{4}{3}\) : \(\frac{5}{4}\)

= \(\frac{2}{3}\)x \(\frac{3}{4}\)x \(\frac{4}{5}\)

= \(\frac{1}{2}\) x \(\frac{4}{5}\)

= \(\frac{2}{5}\)

\(\frac{7}{8}\times\frac{8}{9}\times\frac{9}{10}\)

\(=\frac{7\times8\times9}{8\times9\times10}\)

\(=\frac{7}{10}\)

\(1\times\frac{2}{3}:\frac{4}{3}:\frac{5}{4}\)

\(=\frac{2}{3}\times\frac{3}{4}\times\frac{4}{5}\)

\(=\frac{2}{5}\)

de vay ma ma cung do

1) \(19=\frac{38}{2}=\frac{76}{4}=\frac{95}{5}\)

2) \(1=\frac{3}{3}=\frac{9}{9}=\frac{1000}{1000}\)

~~ Học tốt ~~

\(2=\frac{12}{6}=\frac{14}{7}=\frac{126}{63}\)

\(2=\frac{12}{6}=\frac{14}{7}=\frac{126}{63}\)

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

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

Tính A rồi so sánh:

\(\frac{1}{4}\) + \(\frac{1}{9}\) + \(\frac{1}{16}\) + \(\frac{1}{25}\) + \(\frac{1}{36}\) = \(\frac{1769}{3600}\)

3600 chia hết cho 6, nên ta chọn 3600 làm mẫu số chung.

3600 : 6 = 600

\(\frac{5}{6}\) = \(\frac{5\times600}{6\times600}\) = \(\frac{3000}{3600}\)

Mà \(\frac{3000}{3600}\) > \(\frac{1769}{3600}\)

Nên: \(\frac{5}{6}\) > A

x + 7/6=16/25 

x = 16/25 - 7/6

x =  -79/150.

x - 13/6 = 8/5+3/10

x  - 13/5 =  19/10

x   = 19/10 +13/5 

x    = 9/2

x  : 9/8 = 14/6 

x   = 14/6 * 9/8

x    = 21/8

x * 11/7 = 3/2

x   = 3/2 : 11/7

x   = 21/22

1                                                                                           Bài làm

x + 7/6 = 16/25            x- 13/6 = 8/5 + 3/10           x : 9/8 =14/6            x*11/7 = 3/2

x          = 16/25 - 7/6   x - 13/6 = 3/10 + 8/5           x         = 14/6 * 9/8  x          = 3/2 : 11/7

x          = -79/150        x-   13/6 = 19/10                x          = 21/8           x          = 21/22

                                   x            = 19/10+13/6

                                  x             = 61/15        

b) 1/3+1/3^2+1/3^3+1/3^4+1/3^5 (goi tong bang M)

3M=1+1/3+1/3^2+1/3^3+1/3^4

3M-M=1-1/3^5

2M=242/243

M=242/243*1/2=121/243

^ là gì vậy