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NA
Nguyễn An Ninh
VIP
25 tháng 4 2023
a\()\) 1/2 x 2/3 : 5/6 x 5/6
=2/6 : 35/36
=1/3 x 36/35
=36/105=12/35
b\()\)11x15x56/6x35x38
=165x56/6x35x38
=9240/6x35x38
=1540x35x38
=53900x38
=2,048,200
c\()\) 2/7 x 7/5 + 2/7 - 2/7 x 6/5
=2/7x\(\left(\dfrac{7}{5}-\dfrac{2}{7}\right)\)+2/7
=2/7 x 39/35 + 2/7
=2/7 x \(\left(\dfrac{39}{35}+1\right)\)
=2/7 x 74
=148/7
C
4 tháng 5 2022
a, 2/3 - 2/9 + 7/9 = 6/9 - 2/9 + 7/9 = 10/9
b, 7/6 + 3/5 : 6 = 7/6 + 3/5 x 1/6 = 7/6 + 1/10 = 70/60 + 6/10 = 76/10 = 38/5
c, x : 6/25 = 18
x = 18 x 6/25
x = 36/25
d, ( 2/5 + 4/7) : x = 17/5
29/35 : x = 17/5
x = 29/35 : 17/5
x = 29/119
4 tháng 5 2022
\(a.\dfrac{2}{3}-\dfrac{2}{9}+\dfrac{7}{9}=\dfrac{6}{9}-\dfrac{2}{9}+\dfrac{7}{9}=\dfrac{4}{9}+\dfrac{7}{9}=\dfrac{11}{9}\\ b.\dfrac{7}{6}+\dfrac{3}{5}:6=\dfrac{7}{6}+\dfrac{3}{5}\times\dfrac{1}{6}=\dfrac{7}{6}+\dfrac{1}{10}=\dfrac{70}{60}+\dfrac{6}{60}=\dfrac{76}{60}=\dfrac{19}{15}\\ c.x:\dfrac{6}{25}=18\\ x=18\times\dfrac{6}{25}\\ x=\dfrac{108}{25}\\ d.\left(\dfrac{2}{5}+\dfrac{4}{7}\right):x=\dfrac{17}{5}\\ \dfrac{34}{35}:x=\dfrac{7}{5}\\ x=\dfrac{34}{35}:\dfrac{7}{5}\\ x=\dfrac{34}{49}\)
13 tháng 3 2021
a) 6/7 - 3/6 = 21/42 - 21/42 = 15/42
b) 2/5 x 4/7 = 8/35
c) 3/10 : 6/10 = 3/10 x 10/6 = 1/2
d) 5/9 + 3/4 = 32/36 = 8/9
e) 1/3 : 6 = 1/3 x 1/6 = 1/18
g) 3 x 2/5 = 6/5
h) 6/7 + 4/21 = 22/21
k cho mk nhé!
L
1
11 tháng 4 2023
a: \(=\dfrac{5}{14}\left(\dfrac{2}{9}+\dfrac{7}{9}+1\right)=\dfrac{5}{14}\cdot2=\dfrac{5}{7}\)
b: \(=\dfrac{6}{8}\left(\dfrac{6}{7}-6\right)=\dfrac{6}{8}\cdot\dfrac{-36}{7}=\dfrac{-216}{56}=\dfrac{-27}{7}\)
17 tháng 4 2022
\(\dfrac{3}{4}\times\dfrac{4}{5}\times\dfrac{5}{6}\times\dfrac{6}{7}\div\dfrac{1}{7}\)
\(=\dfrac{3}{4}\times\dfrac{4}{5}\times\dfrac{5}{6}\times\dfrac{6}{7}\times\dfrac{7}{1}\)
\(=\dfrac{3\times4\times5\times6\times7}{4\times5\times6\times7\times1}\)
\(=\dfrac{3}{1}=3\)
14 tháng 5 2023
\(\dfrac{1}{1\times2}+\dfrac{1}{2\times3}+\dfrac{1}{3\times4}+\dfrac{1}{4\times5}+\dfrac{1}{5\times6}+\dfrac{1}{6\times7}+\dfrac{1}{7\times8}\)
\(=1-\dfrac{1}{2}+\dfrac{1}{2}-\dfrac{1}{3}+\dfrac{1}{3}-\dfrac{1}{4}+\dfrac{1}{4}-\dfrac{1}{5}+\dfrac{1}{6}-\dfrac{1}{7}+\dfrac{1}{7}-\dfrac{1}{8}\)
\(=1-\dfrac{1}{8}=\dfrac{7}{8}\)
19 tháng 3 2023
= 51/20
----------------------------------
= 3/14
------------------------------------
= 4/7 - 2/7
= 2/7
--------------------------------------
= 17/45
---------------------------------------
= 2/3
--------------------------------------
= 2 x 1/4
= 1/2
19 tháng 3 2023
5/9xx6/15=30/135=2/9
4/7:24/5=4/7xx5/24=5/42
6/11:4=6/11xx1/4=3/22
12xx19/18=12/1xx19/18=38/3
15 : 25/4=15/1xx4/25=12/5
1212/1515:2727/2525=1212/1515xx2525/2727=20/27
14/27 : 7/18 x 6/5+3/10=14/27xx18/7xx6/5+3/10=4/3xx6/5+3/10=8/5+3/10=16/10+3/10=19/10
NT
Nguyễn Thị Thương Hoài
Giáo viên
VIP
4 tháng 5 2023
a, \(\dfrac{3}{5}\) \(\times\) \(\dfrac{6}{7}\) + \(\dfrac{3}{5}\) : 7 + \(\dfrac{6}{5}\)
= \(\dfrac{3}{5}\) \(\times\) \(\dfrac{6}{7}\) + \(\dfrac{3}{5}\) \(\times\) \(\dfrac{1}{7}\) + \(\dfrac{6}{5}\)
= \(\dfrac{3}{5}\) \(\times\) ( \(\dfrac{6}{7}\) + \(\dfrac{1}{7}\)) + \(\dfrac{6}{5}\)
= \(\dfrac{3}{5}\) + \(\dfrac{6}{5}\)
= \(\dfrac{9}{5}\)
b, 2018 \(\times\) ( \(\dfrac{1}{2}\) + \(\dfrac{1212}{2424}\))
= 2018 \(\times\) ( \(\dfrac{1}{2}\) + \(\dfrac{1}{2}\))
= 2018 \(\times\)1
= 2018
4 tháng 5 2023
a) 3/5 x 6/7 + 3/5 x 1/7 + 6/5
3/5 x ( 6/7 + 1/7 ) + 6/5
3/5 x 7/7 + 6/5
3/5 x 1 + 6/5
3/5 + 6/5
9/5
b) 2018 x ( 1/2 + 1212/ 2424 )
2018 x ( 1/2 + 12/24 )
2018 x ( 1/2 + 1/2 )
2018 x 2/2
2018 x 1
2018
Học tốt
3V
3
O
18 tháng 3 2022
\(\dfrac{1}{2}\times\dfrac{2}{3}\times\dfrac{3}{4}\times\dfrac{4}{5}\times\dfrac{5}{6}\times\dfrac{6}{7}\times\dfrac{7}{8}\times\dfrac{8}{9}\)
\(=\dfrac{1\times2\times3\times4\times5\times6\times7\times8}{2\times3\times4\times5\times6\times7\times8\times9}\)
\(=\dfrac{1}{9}\)
= 6/7 . 3/6 + 2/6 . 6/7 - 6/7 . 1
= 6/7( 3/6 + 2/6 - 1 )
= 6/7 . -1/6
= -1/7
\(\frac{-1}{7}\)