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Bài giải
a, \(\frac{4}{5}-\frac{2}{3}+\frac{1}{5}-\frac{1}{3}\)
\(=\left(\frac{4}{5}+\frac{1}{5}\right)-\left(\frac{2}{3}+\frac{1}{3}\right)=1-1=0\)
b, \(\frac{2}{5}\text{ x }\frac{7}{4}-\frac{2}{5}\text{ x }\frac{3}{7}\)
\(=\frac{2}{5}\text{ x }\left(\frac{7}{4}-\frac{3}{7}\right)=\frac{2}{5}\text{ x }\frac{37}{28}=\frac{37}{70}\)
c, \(\frac{13}{4}\text{ x }\frac{2}{3}\text{ x }\frac{4}{13}\text{ x }\frac{3}{12}=\frac{13\text{ x }2\text{ x }4\text{ x }3}{4\text{ x }3\text{ x }13\text{ x }12}=\frac{1}{6}\)
d, \(\frac{75}{100}+\frac{18}{21}+\frac{19}{32}+\frac{1}{4}+\frac{3}{21}+\frac{13}{32}\)
\(=\frac{3}{4}+\frac{18}{21}+\frac{19}{32}+\frac{1}{4}+\frac{3}{21}+\frac{13}{32}\)
\(=\left(\frac{3}{4}+\frac{1}{4}\right)+\left(\frac{18}{21}+\frac{3}{21}\right)+\left(\frac{19}{32}+\frac{13}{32}\right)\)
\(=1+1+1\)
\(=3\)
e, \(\frac{2}{5}+\frac{6}{9}+\frac{3}{4}+\frac{3}{5}+\frac{1}{3}+\frac{1}{4}\)
\(=\frac{2}{5}+\frac{2}{3}+\frac{3}{4}+\frac{3}{5}+\frac{1}{3}+\frac{1}{4}\)
\(=\frac{1}{5}\left(2+3\right)+\frac{1}{3}\left(2+1\right)+\frac{1}{4}\left(3+1\right)\)
\(=\frac{1}{5}\cdot5+\frac{1}{3}\cdot3+\frac{1}{4}\cdot4\)
\(=1+1+1\)
\(=3\)
a, \(\frac{4}{5}-\frac{2}{3}+\frac{1}{5}-\frac{1}{3}\)
\(=\left(\frac{4}{5}+\frac{1}{5}\right)-\left(\frac{2}{3}+\frac{1}{3}\right)=1-1=0\)
b, \(\frac{2}{5}\text{ x }\frac{7}{4}-\frac{2}{5}\text{ x }\frac{3}{7}\)
\(=\frac{2}{5}\text{ x }\left(\frac{7}{4}-\frac{3}{7}\right)=\frac{2}{5}\text{ x }\frac{37}{28}=\frac{37}{70}\)
c, \(\frac{13}{4}\text{ x }\frac{2}{3}\text{ x }\frac{4}{13}\text{ x }\frac{3}{12}=\frac{13\text{ x }2\text{ x }4\text{ x }3}{4\text{ x }3\text{ x }13\text{ x }12}=\frac{1}{6}\)
d, \(\frac{75}{100}+\frac{18}{21}+\frac{19}{32}+\frac{1}{4}+\frac{3}{21}+\frac{13}{32}\)
\(=\frac{3}{4}+\frac{18}{21}+\frac{19}{32}+\frac{1}{4}+\frac{3}{21}+\frac{13}{32}\)
\(=\left(\frac{3}{4}+\frac{1}{4}\right)+\left(\frac{18}{21}+\frac{3}{21}\right)+\left(\frac{19}{32}+\frac{13}{32}\right)\)
\(=1+1+1\)
\(=3\)
e, \(\frac{2}{5}+\frac{6}{9}+\frac{3}{4}+\frac{3}{5}+\frac{1}{3}+\frac{1}{4}\)
\(=\frac{2}{5}+\frac{2}{3}+\frac{3}{4}+\frac{3}{5}+\frac{1}{3}+\frac{1}{4}\)
\(=\frac{1}{5}\left(2+3\right)+\frac{1}{3}\left(2+1\right)+\frac{1}{4}\left(3+1\right)\)
\(=\frac{1}{5}\cdot5+\frac{1}{3}\cdot3+\frac{1}{4}\cdot4\)
\(=1+1+1\)
\(=3\)
\(2-\frac{3}{4}+x=3-\frac{2}{3}\)
\(2-\frac{3}{4}+x=\frac{7}{3}\)
\(\frac{3}{4}+x=\frac{7}{3}-2\)
\(\frac{3}{4}+x=\frac{1}{3}\)
\(x=\frac{1}{3}-\frac{3}{4}\)
\(x=-\frac{5}{12}\)
\(x-\frac{1}{2}\div\frac{2}{5}=\frac{13}{12}\)
\(x=\frac{13}{12}+\left(\frac{1}{2}\div\frac{2}{5}\right)\)
\(x=\frac{13}{12}+\frac{5}{4}\)
\(x=\frac{7}{3}\)
\(X\times\frac{3}{5}+X\times\frac{2}{5}=\frac{12}{13}\)
\(X\times\left(\frac{3}{5}+\frac{2}{5}\right)=\frac{12}{13}\)
\(X\times1=\frac{12}{13}\)
\(X=\frac{12}{13}:1\)
\(X=\frac{12}{13}\)
kết quả của các số là
24
36
2
đúng ko bạn
nếu ai thấy đúng thì k nha
câu a) lấy mẫu số chung cộng với nhau
câu b) lấy 1 để ngoài nhân r 1/2-1/3 rồi tương tự
10x11+10x12+10x13+10x20
=10x(11+12+13+20)
=10x56
=560
20-10+10-10+2-3=9
x+12=13+12-2
x+12=25-2
x+12=23
x=23-12
x=11
Bài 1:
\(\dfrac{2}{3}\) + \(\dfrac{3}{4}\) - \(\dfrac{2}{5}\)
=\(\dfrac{40}{60}\) + \(\dfrac{45}{60}\) - \(\dfrac{24}{60}\)
= \(\dfrac{61}{60}\)
b; \(\dfrac{12}{13}\) x \(\dfrac{3}{4}\) - \(\dfrac{7}{13}\)
= \(\dfrac{9}{13}\) - \(\dfrac{7}{13}\)
= \(\dfrac{2}{13}\)
c; \(\dfrac{15}{17}\) : \(\dfrac{19}{34}\) - \(\dfrac{17}{19}\)
= \(\dfrac{15}{17}\) x \(\dfrac{34}{19}\) - \(\dfrac{17}{19}\)
= \(\dfrac{30}{19}\) - \(\dfrac{17}{19}\)
= \(\dfrac{13}{19}\)
Bài 2:
a; \(\dfrac{x}{5}\) x \(\dfrac{3}{7}\) = \(\dfrac{9}{35}\)
\(\dfrac{x}{5}\) = \(\dfrac{9}{35}\) : \(\dfrac{3}{7}\)
\(\dfrac{x}{5}\) = \(\dfrac{3}{5}\)
\(x\) = \(\dfrac{3}{5}\) x 5
\(x\) = 3
1a) \(\frac{12}{17}+\frac{19}{17}+\frac{8}{17}\)
\(=\left(\frac{12}{17}+\frac{8}{17}\right)+\frac{19}{17}\)
\(=\frac{20}{17}+\frac{19}{17}\)
\(=\frac{39}{17}\)
b) \(\frac{2}{5}+\frac{7}{12}+\frac{13}{12}\)
\(=\frac{2}{5}+\frac{5}{3}\)
\(=\frac{31}{15}\)
2) \(\frac{25}{3}-x=\frac{5}{6}\)
\(x=\frac{25}{3}-\frac{5}{6}\)
\(x=\frac{45}{6}\)
ủng hộ tớ nha
\(\Rightarrow x=\dfrac{13}{12}-\dfrac{2}{3}=\dfrac{13}{12}-\dfrac{8}{12}=\dfrac{5}{12}\)
là bằng 5/12 nha bạn
k mình nha
học tốt