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DN
17 tháng 3 2022
a) \(\dfrac{12}{5}\)
b) \(\dfrac{1}{6}\)
c) \(\dfrac{6}{7}\)
d) \(\dfrac{8}{45}\)
KP
20 tháng 4 2017
a,Cách 1: (6/11 + 5/11 ) x 3/7 Cách 2 :(6/11 + 5/11) x 3/7
= 1 x 3/7 =6/11 x 3/7 + 5/11 x 3/7
= 3/7 = 18/77 + 15/77
= 3/7
b, Cách 1:3/5 x 7/9 - 3/5 x 2/9 Cách 2 :3/5 x 7/9 - 3/5 x 2/9
= 7/15 - 2/15 = 3/5 x (7/9 - 2/9 )
= 1/3 = 3/5 x 5/9
= 1/3
c, Cách 1:(6/7 - 4/7) : 2/5 Cách 2: ( 6/7- 4/7 ) : 2/5
= 2/7 : 2/5 = 6/7 : 2/5 - 4/7 : 2/5
= 5/7 = 15/7 - 10/7
= 5/7
d,Cách 1:8/15 : 2/11 + 7/15 : 2/11 Cách 2:8/15 : 2/11 +7/15 : 2/11
= 88/30 + 77/30 =(8/15+7/15) :2/11
= 11/2 = 1 : 2/11
= 11/2
Bài 2 cậu tự làm nhé !
28 tháng 3 2023
Bài 1: Tính
a, 1/2 x 2/3 x 3/4 = 1/4
b, 7/8 x 8/9 x 9/10 = 7/10
c, 5/14 x 7/15 x 28/7 = 2/3
d, 2 x 1/2 x 3 x 1/3 x 4 x 1/4 x 5 x 1/5 = 1
Bài 2: Tính
a, 7/20 - ( 5/8 - 3/5 ) = 7/20 - 1/40 = 14/40 - 1/40 = 13/40
b, 5/6 + ( 5/9 - 1/4 ) = 5/6 + 11/36 = 30/36 + 11/36 = 41/36
c, 9/10 - ( 2/5 + 3/10 ) + 7/20 = 9/10 - 7/10 + 7/20 = 2/10 + 7/20 = 4/20 + 7/20 = 11/20.
Bài 3: Tìm x:
a, 1/2 + x = 5/6
x = 5/6 - 1/2
x = 1/3
b, 5/6 - x = 1/3
x = 5/6 - 1/3
x = 1/2
c, x - 1/mấy vậy bạn
d, 1/3 x x = 1/6
x = 1/6 : 1/3
x = 1/2
S
1 tháng 3 2017
a) Cách 1 : (3/4 + 1/2) x 5/7
= 5/4 x 5/7
= 25/28
Cách 2 : (3/4 + 1/2) x 5/7
= 3/4 x 5/7 + 1/2 x 5/7
= 15/28 + 5/14
= 25/28
b) Cách 1 : 5/7 x 13/21 + 2/7 x 13/21
= 65/147 + 26/147
= 13/21
Cách 2 : 5/7 x 13/21 + 2/7 x 13/21
= (5/7 + 2/7) x 13/21
= 1 x 13/21
= 13/21
câu c tự làm
V
13 tháng 4 2017
a] 4/12 ; 5/12 ; 11/2 ; 1/4
b] 1 ; 9/12; 12/5 ; 11/3
c] 8/21; 6/11;8/7
d] 2/3 ;2/7 15/2
13 tháng 4 2017
a]1/3 5/12 11/2 1/4
b]1 3/4 12/5 33/9
c]8/21 6/11 8/7
d]2/3 2/7 15/2
23 tháng 2 2018
\(\frac{5}{7}+\frac{3}{4}=\frac{41}{28}\)\(Đ\)
\(3+\frac{2}{5}=1\)\(S\)
\(\frac{11}{9}-\frac{5}{6}=\frac{7}{18}\)\(Đ\)
\(4-\frac{3}{7}=\frac{25}{7}\)\(Đ\)
\(x+\frac{4}{11}=\frac{3}{5}\).
\(x=\frac{3}{5}-\frac{4}{11}\)
\(x=\frac{13}{55}\)
Vậy ta chọn câu C
23 tháng 2 2018
dung hay sai
5/7 + 3/4 = 41/28 .....Đ...
3 + 2/5 = 1....S....
11/9 - 5/6 = 7/18....Đ...
4 - 3/7 = 25/7.....
tim x
x + 4/11 =3/5
Đáp án : C .13/55
6 tháng 3 2023
Bài 5:
a: =1/3+2/5
=5/15+6/15
=11/15
b: =6/21+12/21=18/21=6/7
c: =16/24+10/24
=26/24
=13/12
d: =4/12+3/12+10/12
=17/12
e: =19/24-9/24
=10/24
=5/12
f: =8/9-3/9=5/9
g: =9/3+1/3=10/3
k: =15/24+42/24+14/24
=71/24
H
18 tháng 4 2023
`a, 3/4 + 1/2 xx 7/2`
`= 3/4 + 7/4`
`=10/4`
`=5/2`
`b, 6/15 - 1/3 : 5/3`
`= 6/15 - 1/3 xx 3/5`
`= 6/15 - 3/15`
`= 3/15`
`=1/5`
`c, x-4/9 = 3/7 : 9/4`
`=> x-4/9= 3/7 xx 4/9`
`=> x-4/9= 12/63`
`=> x-4/9=4/21`
`=> x= 4/21 +4/9`
`=>x= 40/63`
`d, 7/9 xx 3/5 -1/2=1/5`
`->` sao lại bằng có `x` ko vậy ạ?
18 tháng 4 2023
`a,`
`3/4+1/2 \times 7/2=3/4+7/4=10/4=5/2`
`b,`
`6/15 - 1/3 \div 5/3=6/15-1/5=1/5`
`c,` Tìm x?
`x-4/9=3/7 \div 9/4`
`x-4/9=4/21`
`x=4/21+4/9`
`x=40/63`
`d, 7/9x \times 3/5-1/2=1/5`
`7/9x \times 3/5=1/5+1/2`
`7/9x \times 3/5=7/10`
`7/9x=7/10 \div 3/5`
`7/9x=7/6`
`x=7/6 \div 7/9=3/2`
2 tháng 7 2021
1) Ta có: \(\left(\dfrac{3}{4}\cdot\dfrac{5}{97}+\dfrac{1}{9}\cdot\dfrac{13}{47}\right)\cdot\left(\dfrac{1}{5}-\dfrac{7}{25}\cdot\dfrac{5}{7}\right)\)
\(=\left(\dfrac{3}{4}\cdot\dfrac{5}{97}+\dfrac{1}{9}\cdot\dfrac{13}{47}\right)\cdot\left(\dfrac{1}{5}-\dfrac{1}{5}\right)\)
=0
2) Ta có: \(\dfrac{8}{17}\cdot\dfrac{4}{15}+\dfrac{8}{17}\cdot\dfrac{22}{15}-\dfrac{8}{15}\cdot\dfrac{9}{17}\)
\(=\dfrac{8}{17}\left(\dfrac{4}{15}+\dfrac{22}{15}-\dfrac{9}{15}\right)\)
\(=\dfrac{8}{17}\cdot\dfrac{15}{15}=\dfrac{8}{17}\)
3) Ta có: \(\dfrac{2021}{2}\cdot\dfrac{1}{3}+\dfrac{4042}{4}\cdot\dfrac{1}{5}+\dfrac{6063}{3}\cdot\dfrac{22}{15}\)
\(=\dfrac{2021}{2}\left(\dfrac{1}{3}+\dfrac{1}{5}\right)+2021\cdot\dfrac{22}{15}\)
\(=\dfrac{2021}{2}\cdot\dfrac{8}{15}+\dfrac{2021}{2}\cdot\dfrac{44}{15}\)
\(=\dfrac{2021}{2}\cdot\dfrac{52}{15}\)
\(=\dfrac{52546}{15}\)
4) Ta có: \(\dfrac{4}{7}\cdot\dfrac{2}{13}+\dfrac{8}{13}:\dfrac{7}{4}+\dfrac{4}{7}:\dfrac{13}{2}+\dfrac{4}{7}\cdot\dfrac{1}{13}\)
\(=\dfrac{4}{7}\left(\dfrac{2}{13}+\dfrac{8}{13}+\dfrac{2}{13}+\dfrac{1}{13}\right)\)
\(=\dfrac{4}{7}\)
LD
2
NK
22 tháng 3 2023
\(a,\dfrac{1}{3}+\dfrac{3}{4}\times\dfrac{2}{9}=\dfrac{1}{3}+\dfrac{6}{36}=\dfrac{1}{3}+\dfrac{1}{6}=\dfrac{2}{6}+\dfrac{1}{6}=\dfrac{3}{6}=\dfrac{1}{2}\)
\(b,2-\left(\dfrac{2}{5}+\dfrac{2}{3}\right)=2-\left(\dfrac{6}{15}+\dfrac{10}{15}\right)=2-\dfrac{16}{15}=\dfrac{30}{15}-\dfrac{16}{15}=\dfrac{14}{15}\)
\(c,\dfrac{2}{5}:\dfrac{4}{7}+\dfrac{1}{3}=\dfrac{2}{5}\times\dfrac{7}{4}+\dfrac{1}{3}=\dfrac{14}{20}+\dfrac{1}{3}=\dfrac{7}{10}+\dfrac{1}{3}=\dfrac{21}{30}+\dfrac{10}{30}=\dfrac{31}{30}\)
\(d,\dfrac{9}{13}:\dfrac{3}{26}-\dfrac{8}{13}=\dfrac{9}{13}\times\dfrac{26}{3}-\dfrac{8}{13}=\dfrac{234}{39}-\dfrac{8}{13}=6-\dfrac{8}{13}=\dfrac{78}{13}-\dfrac{8}{13}=\dfrac{70}{13}\)
22 tháng 3 2023
a:=1/3+6/36
=1/3+1/6
=1/2
b: =2-16/15
=14/15
c: =2/5*7/4+1/3
=14/20+1/3
=7/10+1/3
=21/30+10/30=31/30
d: =9/13*26/3-8/13
=3-8/13=31/13
a . 4 5 + 1 3 = 12 15 + 5 15 = 12 + 5 15 = 17 15
b . 2 3 : 4 = 2 3 : 4 1 = 2 3 × 1 4 = 2 12 = 1 6
c . 13 7 - 7 7 = 13 - 7 7 = 6 7
d . 4 9 x 2 5 = 4 × 2 9 × 5 = 8 45