9000g=9kg=0,9 yến

5,78 tạ=5780hg=578kg

123kg=1230 lạng=1,23 tạ

9000g=.....9......kg=.....0,9.....yến

5,78 tạ=....5780....hg=....578....kg

123kg=....1230...........lạng=....1,23......tạ

25 kg=........2,5.......yến=....2500........dag

2,45 yến=.........24500........g=....245........hg

46 yến=............4,6.........tạ=.......0,46..........tấn

5,98 lạng=........59,8..........dag=.......598............g

4507 kg=.......45,07........tạ=.....4,507........tấn 

25 kg=2,5 yến=2500dag

2,45 yến=24500g=245hg

46 yến=4,6 tạ=0,46 tấn

5,98 lạng=59,8 dag =598g

ụa toán mà:v

39/5 + ( 9/4 - 9/5 ) - ( 5/4 + 6/7 )

= 39/5 + 9/20 - 59/28

= 33/4 - 59/28

= 43/7 

mk ko nghi lại đề nx nhé.

= { [ ( -0,56)² : 49/125 ] . 5/6 } - ( 1/6 )

=( 0,8 . 5/6)  - 1/6

=  ( 8/10 . 5/6 ) - 1/6

= ( 4/5 . 5/6 ) - 1/6

= 2/3 - 1/6

= 1/2 

=\(\left\{\left[\left(\dfrac{1}{25}-\dfrac{3}{5}\right)^2:\dfrac{49}{125}\right].\dfrac{5}{6}\right\}-\left[\left(\dfrac{-2}{6}\right)+\dfrac{3}{6}\right]\)

\(=\left\{\left[\left(\dfrac{1}{25}-\dfrac{15}{25}\right)^2:\dfrac{49}{125}\right].\dfrac{5}{6}\right\}-\dfrac{1}{6}\)

\(=\left\{\left[\left(\dfrac{-14}{25}\right)^2:\dfrac{49}{125}\right].\dfrac{5}{6}\right\}-\dfrac{1}{6}\)

\(=\left\{\left[\dfrac{196}{625}.\dfrac{125}{49}\right].\dfrac{5}{6}\right\}-\dfrac{1}{6}\)

\(=\left\{\dfrac{4}{5}.\dfrac{5}{6}\right\}-\dfrac{1}{6}\)

\(=\dfrac{2}{3}-\dfrac{1}{6}\)

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

\(=\dfrac{3}{6}=\dfrac{1}{2}\)

2/7>9/49

3/8>4/72

5/6>1/42

5/12>7/36

4/9>7/54

So sánh 2 phân số:

\(\dfrac{2}{7}\) và \(\dfrac{9}{49}\)

\(\dfrac{2}{7}=\dfrac{2\times49}{7\times49\text{​}}=\dfrac{98}{343}\)

\(\dfrac{9}{49}=\dfrac{9\times7}{49\times7}=\dfrac{63}{343}\)

Vì: 98 > 63

Nên: \(\dfrac{2}{7}>\dfrac{9}{49}\)

\(\dfrac{3}{8}\) và \(\dfrac{4}{72}\)

\(\dfrac{3}{8}=\dfrac{3\times72}{8\times72}=\dfrac{216}{576}\\ \dfrac{4}{72}=\dfrac{4\times8}{72\times8}=\dfrac{32}{576}\)

Vì: 216 > 32

Nên: \(\dfrac{3}{8}>\dfrac{4}{72}\)

\(\dfrac{5}{6}\) và \(\dfrac{1}{42}\)

\(\dfrac{5}{6}=\dfrac{5\times42}{6\times42}=\dfrac{210}{252}\\ \dfrac{1}{42}=\dfrac{1\times6}{42\times6}=\dfrac{6}{252}\)

Vì: \(210>6\)

Nên: \(\dfrac{5}{6}>\dfrac{1}{42}\)

\(\dfrac{5}{12}\)  và \(\dfrac{7}{36}\)

\(\dfrac{5}{12}=\dfrac{5\times36}{12\times36}=\dfrac{180}{432}\\ \dfrac{7}{36}=\dfrac{7\times12}{36\times12}=\dfrac{84}{432}\)

Vì: 180 > 84

Nên:  \(\dfrac{5}{12}>\dfrac{7}{36}\)

\(\dfrac{4}{9}\) và \(\dfrac{7}{54}\)

\(\dfrac{4}{9}=\dfrac{4\times54}{9\times54}=\dfrac{216}{486}\\ \dfrac{7}{54}=\dfrac{7\times9}{54\times9}=\dfrac{63}{486}\)

Vì: 216 > 63

Nên: \(\dfrac{4}{9}>\dfrac{7}{54}\)