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Bài 7:
Số phần kẹo Hùng đã cho Hà và Hồng là:
\(\dfrac{2}{7}+\dfrac{1}{7}=\dfrac{3}{7}\left(phần\right)\)
Hùng còn lại số phần của gói kẹo là:
\(\dfrac{6}{7}-\dfrac{3}{7}=\dfrac{3}{7}\left(phần\right)\)
1:
2 3/4
5 6/5
3 3/9
7 6/8
2:
1/3 + 2/3 + (3/4 + 1/4) = 2
=2
= 4 5/10
\(\dfrac{4}{7}-\dfrac{1}{7}.\dfrac{10}{13}\)
\(=\dfrac{4}{7}-\dfrac{10}{91}\)
\(=\dfrac{52}{91}-\dfrac{10}{91}\)
\(=\dfrac{42}{91}=\dfrac{6}{13}\)
_______
\(\dfrac{1}{8}+\dfrac{1}{6}:\dfrac{2}{3}\)
\(=\dfrac{1}{8}+\dfrac{1}{6}.\dfrac{3}{2}\)
\(=\dfrac{1}{8}+\dfrac{1}{4}\)
\(=\dfrac{1}{8}+\dfrac{2}{8}\)
\(=\dfrac{3}{8}\)
___________
\(\left(\dfrac{7}{9}-\dfrac{2}{18}\right):\dfrac{4}{7}\)
\(=\left(\dfrac{14}{18}-\dfrac{2}{18}\right).\dfrac{7}{4}\)
\(=\dfrac{12}{18}.\dfrac{7}{4}\)
\(=\dfrac{7}{6}\)
\(#WendyDang\)
Lời giải:
$\frac{4}{7}-\frac{1}{7}\times \frac{10}{13}=\frac{1}{7}\times 4-\frac{1}{7}\times \frac{10}{13}$
$=\frac{1}{7}\times (4-\frac{10}{13})=\frac{1}{7}\times \frac{42}{13}$
$=\frac{42}{7\times 13}=\frac{6\times 7}{7\times 13}=\frac{6}{13}$
-----------------
$\frac{1}{8}+\frac{1}{6}: \frac{2}{3}=\frac{1}{8}+\frac{1}{6}\times \frac{3}{2}=\frac{1}{8}+\frac{1}{4}=\frac{1}{8}+\frac{2}{8}=\frac{3}{8}$
------------------
$(\frac{7}{9}-\frac{2}{18}): \frac{4}{7}=(\frac{7}{9}-\frac{1}{9})\times \frac{7}{4}$
$=\frac{6}{9}\times \frac{7}{4}=\frac{2}{3}\times \frac{7}{4}=\frac{7}{6}$
`4/7+4`
`=4/7+4/1`
`=4/7+28/7`
`=32/7`
__
`3+6/11`
`=33/11+6/11`
`=39/11`
__
`3-5/7`
`=3/1-5/7`
`=21/7-5/7`
`=16/7`
__
`21/9-2`
`=21/9-18/9`
`=3/9`
`=1/3`
__
`15/24+2`
`=15/24+48/24`
`=63/24`
`=21/16`
__
`63/45-20/25`
`=63/45-4/5`
`=63/45-36/45`
`=27/45`
`=9/15`
__
`3/4-2/8`
`=3/4-1/4`
`=2/4`
__
`6/7-5/8`
`=48/56-35/56`
`=13/56`
__
`37/45-5/9`
`=37/45-25/45`
`=12/45`
`=4/15`
__
`46/39-11/13`
`=46/39-33/39`
`=13/39`
`=1/2`
__
`5/12+3/4+1/3`
`=5/12+9/12+4/12`
`=14/12+4/12`
`=18/12`
`=3/2`
__
`1/2+3/7+11/14`
`=7/14+6/14+11/14`
`=13/14+11/14`
`=24/14`
`=12/7`
__
`7/10-(1/5+1/4)`
`=7/10-(4/20+5/20)`
`=7/10-9/20`
`=14/20-9/20`
`=5/20`
`=1/4`
__
`15/4-2/3-3/4`
`=(15/4-3/4)-2/3`
`=12/4-2/3`
`=3-2/3`
`=9/3-2/3`
`=7/3`
1:
a: =8/7-5/88=669/616
b: \(=1+\dfrac{2}{9}\cdot\dfrac{3}{7}-\dfrac{10}{7}=1+\dfrac{2}{21}-\dfrac{10}{7}\)
\(=\dfrac{21+2-30}{21}=\dfrac{-7}{21}=\dfrac{-1}{3}\)
c: \(=\dfrac{11}{3}-\dfrac{6}{7}+4=\dfrac{77-18+84}{21}=\dfrac{143}{21}\)
Bài 2:
a: =>9/4-x=5/11*2=10/11
=>x=9/4-10/11=59/44
b: =>2/9:x=19/21
=>x=2/9:19/21=14/57
Bài 1:
a: x+1/2=5/6
nên x=5/6-1/2=1/3
b: x+1/4=3/4
nên x=3/4-1/4=2/4=1/2
c: x+3/10=1/2
nên x=1/2-3/10=5/10-3/10=1/5
d: x+1/4=3/8
nên x=3/8-1/4=3/8-2/8=1/8
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
\(\left(\dfrac{1}{2}+\dfrac{4}{7}\right)-\left(\dfrac{3}{7}-\dfrac{3}{10}\right)\)
\(=\dfrac{1}{2}+\dfrac{4}{7}-\dfrac{3}{7}+\dfrac{3}{10}\)
\(=\left(\dfrac{1}{2}+\dfrac{3}{10}\right)-\left(\dfrac{4}{7}+\dfrac{3}{7}\right)\)
\(=\left(\dfrac{5}{10}+\dfrac{3}{10}\right)-1\)
\(=\dfrac{8}{10}-1\)
\(=\dfrac{8}{10}-\dfrac{10}{10}\)
\(=\dfrac{-2}{10}\)
Mình làm ra kết quả là âm, không biết do mình làm sai hay đề bài sai. Mình làm sai, mong mọi người đừng chửi mình nha.
\(\left(\dfrac{1}{2}+\dfrac{4}{7}\right)-\left(\dfrac{3}{7}-\dfrac{3}{10}\right)\)
\(=\dfrac{1}{2}+\dfrac{4}{7}-\dfrac{3}{7}+\dfrac{3}{10}\)
\(=\left(\dfrac{1}{2}+\dfrac{3}{10}\right)+\left(\dfrac{4}{7}-\dfrac{3}{7}\right)\)
\(=\left(\dfrac{5}{10}+\dfrac{3}{10}\right)+\dfrac{1}{7}\)
\(=\dfrac{8}{10}+\dfrac{1}{7}\)
\(=\dfrac{4}{5}+\dfrac{1}{7}\)
\(=\dfrac{28}{35}+\dfrac{5}{35}\)
\(=\dfrac{33}{35}\)