Hỗn số

a: \(=3+\dfrac{1}{2}+2+\dfrac{2}{5}=5+\dfrac{9}{10}=\dfrac{59}{10}\)

s: \(=\dfrac{2}{6}+\dfrac{63}{6}=\dfrac{65}{6}\)

b: \(\dfrac{53}{8}-\dfrac{12}{3}=\dfrac{53}{8}-4=\dfrac{21}{8}\)

\(3\dfrac{2}{5}=\dfrac{3\times5+2}{5}=\dfrac{17}{5}\)                                          \(2\dfrac{4}{9}=\dfrac{2\times9+4}{9}=\dfrac{22}{9}\)
 

\(7\dfrac{3}{8}=\dfrac{7\times8+3}{8}=\dfrac{59}{8}\)                                          \(15\dfrac{1}{10}=\dfrac{15\times10+1}{10}=\dfrac{151}{10}\)

Câu 2 :

\(3\dfrac{2}{5}=\dfrac{3\times5+2}{5}==\dfrac{17}{5}\)

\(2\dfrac{4}{9}=\dfrac{2\times9+4}{9}=\dfrac{22}{9}\)

\(7\dfrac{3}{8}=\dfrac{7\times8+3}{8}=\dfrac{59}{8}\)

\(15\dfrac{1}{10}=\dfrac{15\times10+1}{10}=\dfrac{151}{10}\)

\(3\dfrac{2}{5}=\dfrac{3\times5+2}{5}=\dfrac{17}{5}\)

\(2\dfrac{4}{9}=\dfrac{2\times9+4}{9}=\dfrac{22}{9}\)

\(7\dfrac{3}{8}=\dfrac{7\times8+3}{8}=\dfrac{59}{8}\)

\(15\dfrac{1}{10}=\dfrac{15\times10+1}{10}=\dfrac{151}{10}\)

`a, 11/3 + 1 1/2`

`= (22+9)/6`

`= 31/6`

`b, 31/2 xx 11/7`

`= 341/14`

`c, 32/5 - 11/10`

`= (64-11)/10 = 53/10`

`d, 41/6 : 21/3`

`= 41/6 xx 1/7`

`= 41/42`

\(a,1\dfrac{1}{3}+2\dfrac{1}{2}=\dfrac{4}{3}+\dfrac{5}{2}=\dfrac{23}{6}\)

\(b,3\dfrac{2}{5}-1\dfrac{1}{10}=\dfrac{17}{5}-\dfrac{11}{10}=\dfrac{23}{10}\)

\(c,3\dfrac{1}{2}\times1\dfrac{1}{7}=\dfrac{7}{2}\times\dfrac{8}{7}=4\)

\(d,4\dfrac{1}{6}:2\dfrac{1}{3}=\dfrac{25}{6}:\dfrac{7}{3}=\dfrac{25}{14}\)

`a) 35/9 > 27/9 (vì : 35>27)`

`b) 54/10 < 52/5 = 104/10 (vì : 104 > 54)`

`c)31/2 = 155/10 > 13/5 = 26/10 (vì : 155 > 26)`

`d) 41/8 <33/4 = 66/8 (vì : 41<66)`

Đổi \(1\dfrac{1}{3}=\dfrac{4}{3};7\dfrac{1}{2}=\dfrac{15}{2}\)

\(\dfrac{15}{2}\) giây bánh xe quay được số vòng là:

\(\dfrac{4}{3}\times\dfrac{15}{2}=10\) ( vòng )

Đ/s: 10 vòng

=13/5

\(=\dfrac{2\times5+3}{5}=\dfrac{13}{5}\)

13/5

`2 1/4 + 2 1/25 - 3 2/5 xx 1 1/10`

`=9/4 + 51/25 - 17/5 xx 11/10`

`=9/4 + 51/25 - (17xx11)/(5xx10)`

`=9/4 + 51/25 - 187/50`

`=225/100 + 204/100 - 374/100`

`=(225+204-374)/100`

`=55/100`

`=11/20`

\(2\dfrac{1}{4}+2\dfrac{1}{25}-3\dfrac{2}{5}x1\dfrac{1}{10}=\dfrac{9}{4}+\dfrac{51}{25}-\dfrac{17}{5}x\dfrac{11}{10}=\dfrac{9}{4}+\dfrac{51}{25}-\dfrac{187}{50}=\dfrac{225}{100}+\dfrac{204}{100}-\dfrac{374}{100}=\dfrac{55}{100}=\dfrac{11}{20}\)

cả 2 bài ạ

Bài 2:

a: 1/5h=12 phút

b: 1+1/2h=1,5h=90 phút

c: 1/3 phút=20 giây

d: 2+1/4 phút=2,25 phút=135 giây

1:

a: =15/7*31/8=465/56

b: =29/5-7/6=139/30

c: =25/6+19/5=239/30

2:

a: =44/5:7/2=88/35

b: =10/3+11/9+5/9=46/9