a: \(\dfrac{31995-81}{42660-108}=\dfrac{31914}{42552}=\dfrac{3}{4}\)

b: \(\dfrac{3\cdot5\cdot7\cdot11\cdot13\cdot37-10101}{1212120+40404}=\dfrac{545454}{1252524}=\dfrac{27}{62}\)

a, $\frac{31995-81}{42660-108}$

= $\frac{395.81-81}{395.108-108}$

=$\frac{81.394}{394.108}$

= $\frac{81}{108}$          = $\frac{3}{4}$

b, $\frac{3.5.7.11.13.37-10101}{1212120+40404}$

= $\frac{3.5.7.11.13.37-3.7.13.37}{\mathrm{3.7.12.13.37.10}+\mathrm{3.4.7.13.37}}$

= $\frac{\left(\mathrm{3.7.13.37}\right)(5.11-1)}{\left(\mathrm{3.7.13.37}\right)(120+4)}$

= $\frac{5.11-1}{120+4}$

= $\frac{54}{124}$ = $\frac{27}{62}$

31995 - 81 / 42660 - 108 

= 31914 / 42552 

= 3.10638 / 4.10638 

= 3/4

=3/4

tk mk nha 

31995 - 81 / 42660 - 108 
= 31914 / 42552 
= 3.10638 / 4.10638 
= 3/4

:3

A = \(\frac{3^4\left(5.79-1\right)}{2^2.3^2\left(5.79-1\right)}=\frac{9}{4}\); B = \(\frac{3.7.13.37\left(5.11-1\right)}{4.3.7.13.37\left(3.5-1\right)}=\frac{54}{4.14}=\frac{2.9}{4.2.7}=\frac{9}{28}\)

Ta có:

\(\begin{array}{l}\frac{{24}}{{108}} = \frac{{24:12}}{{108:12}} = \frac{2}{9};\\\frac{{80}}{{32}} = \frac{{80:16}}{{32:16}} = \frac{5}{2}\end{array}\)

Tổng số phần bằng nhau là :

    5 + 7 = 12 ( phần )

Tử số của phân số \(\frac{a}{b}\)là :

   108 : 12 x 5 = 45

Mẫu số của phân số \(\frac{a}{b}\)là : 

   108 - 45 = 63 

Vậy phân số chúng ta cần tìm là \(\frac{45}{63}\).

very good

em muốn nhanh thì lần sau em tách câu hỏi ra chứ đừng hỏi nhiều trong một câu em nhé

\(\dfrac{12}{48}\) = \(\dfrac{12:12}{48:12}=\)  \(\dfrac{1}{2}\)                            \(\dfrac{49}{140}\) = \(\dfrac{49:7}{140:7}\) = \(\dfrac{7}{20}\)

\(\dfrac{125}{1000}\) = \(\dfrac{125:125}{1000:125}\) = \(\dfrac{1}{8}\)               \(\dfrac{352}{253}\) = \(\dfrac{352:11}{253:11}\)= \(\dfrac{32}{23}\)

\(\dfrac{75}{300}=\) \(\dfrac{75:75}{300:75}\) = \(\dfrac{1}{4}\)                 \(\dfrac{561}{132}\) = \(\dfrac{561:33}{132:33}\) = \(\dfrac{17}{4}\)

Giúp mình nhanh với ạ

Rút gọn các phân số sau                      16/36 72 / 120 39 / 13 / 145 36/108 35/84

D. \(\dfrac{1}{2}\)

1/2

\(\dfrac{54}{108}\) = \(\dfrac{54:54}{108:54}\) = \(\dfrac{1}{2}\)

Chọn d 1/2

A=1/2=3/6

B=2/3=4/6

cách làm bạn à

\(A=\dfrac{3469-54}{6938-108}\)

\(A=\dfrac{3415}{6830}\)

\(A=\dfrac{3415}{6830}=\dfrac{3415:3415}{6830:3415}=\dfrac{1}{2}=\dfrac{3}{6}\)

\(B=\dfrac{2468-98}{3702-147}\)

\(B=\dfrac{2370}{3555}\)

\(B=\dfrac{2370}{3555}=\dfrac{2370:1185}{3555:1185}=\dfrac{2}{3}=\dfrac{4}{6}\)

A = \(\frac{3469-54}{6938-108}\)

= \(\frac{3469-54}{2\left(3469-54\right)}\)

= \(\frac{1}{2}\)

B = \(\frac{2468-98}{3702-147}\)

= \(\frac{2\left(1234-49\right)}{3\left(1234-49\right)}\)

= \(\frac{2}{3}\)

BCNN(2,3) = 6

\(\frac{1}{2}=\frac{1.3}{2.3}=\frac{3}{6}\)

\(\frac{2}{3}=\frac{2.2}{3.2}=\frac{4}{6}\)

\(A=\frac{3469-54}{6938-108}=\frac{3469-54}{3469.2-54.2}=\frac{3469-54}{2.\left(3469-54\right)}=\frac{1}{2}=\frac{1.3}{2.3}=\frac{3}{6}\)

\(B=\frac{2468-98}{3702-147}=\frac{1234.2-49.2}{1234.3-49.3}=\frac{2.\left(1234-49\right)}{3.\left(1234-49\right)}=\frac{2}{3}=\frac{2.2}{3.2}=\frac{4}{6}\)