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NK
17 tháng 3 2023
\(\dfrac{2}{9}+\dfrac{3}{7}+\dfrac{15}{13}+\dfrac{4}{7}-\dfrac{2}{13}+\dfrac{7}{9}\)
\(=\left(\dfrac{2}{9}+\dfrac{7}{9}\right)+\left(\dfrac{3}{7}+\dfrac{4}{7}\right)+\left(\dfrac{15}{13}-\dfrac{2}{13}\right)\)
\(=\dfrac{9}{9}+\dfrac{7}{7}+\dfrac{13}{13}=1+1+1=3\)
20 tháng 5 2022
2/3 + 3/4=17/12
9/4 + 3/5=57/20
5/24 + 1/4=11/24
3/15 - 5/35=2/35 18/27 - 2/6=1/3 37/12 - 3=1/12
11/9 x 3/22=1/6 7/13 x 13/7=1 4 x6/7=24/7
2/5 : 3/10=4/3 3/8 : 9/4=1/6 8/21 : 4/7=2/3
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: \(\dfrac{4}{7}\cdot\dfrac{2}{13}+\dfrac{8}{13}:\dfrac{7}{4}+\dfrac{4}{7}:\dfrac{13}{2}+\dfrac{4}{7}\cdot\dfrac{1}{13}\)
\(=\dfrac{4}{7}\left(\dfrac{2}{13}+\dfrac{8}{13}+\dfrac{2}{13}+\dfrac{1}{13}\right)\)
\(=\dfrac{4}{7}\)
PT
0
DN
17 tháng 3 2022
a) \(\dfrac{12}{5}\)
b) \(\dfrac{1}{6}\)
c) \(\dfrac{6}{7}\)
d) \(\dfrac{8}{45}\)
TT
2
VN
Võ Ngọc Phương
VIP
7 tháng 10 2023
\(\dfrac{4}{7}-\dfrac{1}{7}.\dfrac{10}{13}\)
\(=\dfrac{4}{7}-\dfrac{10}{91}\)
\(=\dfrac{52}{91}-\dfrac{10}{91}\)
\(=\dfrac{42}{91}=\dfrac{6}{13}\)
_______
\(\dfrac{1}{8}+\dfrac{1}{6}:\dfrac{2}{3}\)
\(=\dfrac{1}{8}+\dfrac{1}{6}.\dfrac{3}{2}\)
\(=\dfrac{1}{8}+\dfrac{1}{4}\)
\(=\dfrac{1}{8}+\dfrac{2}{8}\)
\(=\dfrac{3}{8}\)
___________
\(\left(\dfrac{7}{9}-\dfrac{2}{18}\right):\dfrac{4}{7}\)
\(=\left(\dfrac{14}{18}-\dfrac{2}{18}\right).\dfrac{7}{4}\)
\(=\dfrac{12}{18}.\dfrac{7}{4}\)
\(=\dfrac{7}{6}\)
\(#WendyDang\)
AH
Akai Haruma
Giáo viên
7 tháng 10 2023
Lời giải:
$\frac{4}{7}-\frac{1}{7}\times \frac{10}{13}=\frac{1}{7}\times 4-\frac{1}{7}\times \frac{10}{13}$
$=\frac{1}{7}\times (4-\frac{10}{13})=\frac{1}{7}\times \frac{42}{13}$
$=\frac{42}{7\times 13}=\frac{6\times 7}{7\times 13}=\frac{6}{13}$
-----------------
$\frac{1}{8}+\frac{1}{6}: \frac{2}{3}=\frac{1}{8}+\frac{1}{6}\times \frac{3}{2}=\frac{1}{8}+\frac{1}{4}=\frac{1}{8}+\frac{2}{8}=\frac{3}{8}$
------------------
$(\frac{7}{9}-\frac{2}{18}): \frac{4}{7}=(\frac{7}{9}-\frac{1}{9})\times \frac{7}{4}$
$=\frac{6}{9}\times \frac{7}{4}=\frac{2}{3}\times \frac{7}{4}=\frac{7}{6}$
XO
7 tháng 5 2019
A =\(\frac{2}{5}\times\frac{4}{7}+\frac{3}{5}\times\frac{4}{7}\) B = \(\frac{17}{13}\times\frac{12}{17}-\frac{4}{13}\times\frac{12}{17}\) C = \(\frac{9}{14}:\frac{6}{7}+\frac{5}{14}:\frac{6}{7}\) D =\(\frac{9}{12}:\frac{7}{9}\times\frac{12}{19}\)
= \(\frac{4}{7}\times\left(\frac{2}{5}+\frac{3}{5}\right)\) =\(\left(\frac{17}{13}-\frac{4}{13}\right)\times\frac{12}{17}\) = \((\frac{9}{14}+\frac{5}{14}):\frac{6}{7}\) = \(\frac{9}{12}\times\frac{9}{7}\times\frac{12}{19}\)
=\(\frac{4}{7}\times1\) = \(1\times\frac{12}{17}\) = \(1:\frac{6}{7}\) = \(\frac{9\times9\times12}{12\times7\times19}\)
=\(\frac{4}{7}\) = \(\frac{12}{17}\) =\(\frac{7}{6}\) = \(\frac{9\times9}{7\times19}=\frac{81}{133}\)
=(3/7+4/7)+(2/9+7/9)-2/13=2-2/13=24/13
= (3/7+4/7) + (2/9+7/9) - 2/13 = 2 - 2/13 = 24/13