a) \(\dfrac{17}{8}-2=\dfrac{1}{8}\)

b) \(\dfrac{189}{45}-3=\dfrac{6}{5}\)

c) \(3-\dfrac{5}{7}=\dfrac{16}{7}\)

d) \(5-\dfrac{1515}{1818}=\dfrac{25}{6}\)

\(\frac{1717}{1919}.\frac{303}{1818}+\frac{1717}{1919}.\frac{1515}{1818}\)

\(=\frac{1717}{1919}.\left(\frac{303}{1818}+\frac{1515}{1818}\right)\)

\(=\frac{1717}{1919}.1\)

\(=\frac{17}{19}\)

Dấu "." là dấu " x " 

học tốt!!!

\(A=\frac{17\cdot101}{19\cdot101}\cdot\frac{1\cdot303}{6\cdot303}+\frac{17\cdot101}{19\cdot101}\cdot\frac{5\cdot303}{6\cdot303}\) 

\(=\frac{17}{19}\cdot\frac{1}{6}+\frac{17}{19}\cdot\frac{5}{6}\) 

\(=\frac{17}{19}\cdot\left(\frac{5}{6}+\frac{1}{6}\right)\) 

\(=\frac{17}{19}\cdot1\) 

\(=\frac{17}{19}\)

\(A=\frac{17}{19}x\frac{1}{6}+\frac{17}{19}x\frac{5}{6}\)

     \(=\frac{17}{19}x\left(\frac{1}{6}+\frac{5}{6}\right)=\frac{17}{19}x1=\frac{17}{19}\)

A= \(\frac{1717}{1919}\text{ *}\frac{303}{1818}+\frac{17}{19}\text{ *}\frac{1515}{1818}\)

A= \(\frac{17}{19}\text{ *}\frac{3}{18}+\frac{17}{19}\text{ *}\frac{15}{18}\)

A= \(\frac{17}{19}\text{ *}\left(\frac{3}{18}+\frac{15}{18}\right)\)

A= \(\frac{17}{19}\text{ *}1\)

A= \(\frac{17}{19}\)

Vậy A= \(\frac{17}{19}\)

vVv Học tốt nhé bạn, mình sẽ rất vui nếu bạn k đúng cho mình, cảm ơn ban nhiều vVv

\(\frac{1717}{1919}x\frac{303}{1818}+\frac{17}{19}x\frac{1515}{1818}\)

= \(\frac{17}{19}x\frac{1}{6}\)+ \(\frac{17}{19}x\frac{5}{6}\) 

= \(\frac{17}{19}\)x ( \(\frac{1}{6}+\frac{5}{6}\))

= \(\frac{17}{19}x1\)

= \(\frac{17}{19}\) 

18/15*35/36+18/15*15/18-18/15*20/72

5/6+1/1-1/3

5/6+6/6-2/6

3/2

Đề bài kiểu gì vậy?VIết rõ hơn đi

rối mắt á

1414+1515+1616+1717+1818+1919

2020+2121+2222+2323+2424+2525

So sánh 6262 / 7878 và 2424 / 3636

 Vì 6262/7878 > 2424/3636

Nên 1414 + 1515 + 1616 + 1717 / 1818 + 1919 + 2020 + 2121 > 2424/3636