Bài 2:
$8\frac{2}{5}=\frac{42}{5}$
$5\frac{3}{4}=\frac{23}{4}$
$4\frac{3}{7}=\frac{31}{7}$
$2\frac{1}{10}=\frac{21}{10}$
Bài 3:
a.
1 dm = $\frac{1}{10}$ m
3 dm = $\frac{3}{10}$ m
9 dm = $\frac{9}{10}$ m
b.
1 g = $\frac{1}{1000}$ kg
8 g = $\frac{8}{1000}=\frac{1}{125}$ kg
25 g = $\frac{25}{1000}=\frac{1}{40}$ kg
c.
1 phút $=\frac{1}{60}$ giờ
6 phút $=\frac{6}{60}=\frac{1}{10}$ giờ
12 phút $=\frac{12}{60}=\frac{1}{5}$ giờ
Bài 4:
5m7dm=57dm
2m3dm=23dm
4m37cm=437cm
1m53cm=153cm
Bài 2:
\(8\dfrac{2}{5}=\dfrac{42}{5}\)
\(5\dfrac{3}{4}=\dfrac{23}{4}\)
\(4\dfrac{3}{7}=\dfrac{31}{7}\)
\(2\dfrac{1}{10}=\dfrac{21}{10}\)
Bài 3:
a: \(1dm=\dfrac{1}{10}m\)
\(3dm=\dfrac{3}{10}m\)
\(9dm=\dfrac{9}{10}m\)
b: \(1g=\dfrac{1}{1000}kg\)
\(8g=\dfrac{1}{125}kg\)
\(25g=\dfrac{1}{40}kg\)
c: \(1'=\dfrac{1}{60}h\)
\(6'=\dfrac{1}{10}h\)
\(12'=\dfrac{1}{5}h\)
