1 ,62/23,15/23,13/23,12/23

2, 5/6,3/4,2/3,7/12

2 

a 3/5-1/15x101/3= 3/5-10/165=99/165-10/165=88/165=8/15

b 1/2+3/8:3/4=1/2+3/8x4/3=1/2+1/2=2/2=1

c (3/5-3/20)x4-5=(12/20-3/20)x4/5=9/20x4/5=36/100=9/25

Vote mk 5s+cm+ctlhn nha!

Đáp án + Giải thích các bước giải:

Bài 1 : 

15 13 62 12

a) $\frac{62}{23}$; $\frac{15}{23}$; $\frac{13}{23}$ ; $\frac{12}{23}$  

b) Ta quy đồng : $\frac{3}{4}$ = $\frac{3*3}{4*3}$ = $\frac{9}{12}$ ; 

$\frac{2}{3}$ = $\frac{2*4}{3*4}$ = $\frac{8}{12}$; $\frac{5}{6}$ = $\frac{5*2}{6*2}$ = $\frac{10}{12}$

giữ nhuyên $\frac{7}{12}$

Ta có : $\frac{10}{12}$; $\frac{9}{12}$; $\frac{8}{12}$; $\frac{7}{12}$; 

Vậy ta sắp xếp được : $\frac{5}{6}$; $\frac{3}{4}$; $\frac{2}{3}$; $\frac{7}{12}$

Bài 2 :

a) $\frac{3}{5}$ - $\frac{1}{15}$ x $\frac{10}{13}$ = $\frac{3}{5}$ - $\frac{2}{39}$ 

= $\frac{117}{195}$ - $\frac{10}{195}$ 

= $\frac{107}{195}$ .

b) $\frac{1}{2}$ + $\frac{3}{8}$ : $\frac{3}{4}$ = $\frac{1}{2}$ + $\frac{1}{2}$

= $\frac{1}{2}$ + $\frac{4}{2}$

= 1.

c) ( $\frac{3}{5}$ - $\frac{3}{20}$ ) x $\frac{4}{5}$ = $\frac{9}{20}$ x $\frac{4}{5}$

= $\frac{9}{25}$ .

Xin hay nhất ạ !

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