Question

[kaka]

                             Giúp mình bài 7,8 nhớ giải chi tiế nha

Answer 1

[Nguyễn Kim Ngân]

Câu 7 :

\(a,\)\(18\) + \(\frac{9}{3}\)=\(\frac{18}{1}\)+\(\frac{9}{3}\)= \(\frac{54}{3}\)+\(\frac{9}{3}\)=\(\frac{63}{3}\)= \(21\)

\(b,\)\(\frac{4}{9}\)- \(\frac{5}{18}\)= \(\frac{72}{162}\)- \(\frac{45}{162}\)= \(\frac{27}{162}\)= \(\frac{1}{6}\)

\(c,\)\(\frac{3}{5}\)\(:\)\(\frac{5}{7}\)= \(\frac{3}{5}\)x \(\frac{7}{5}\)= \(\frac{21}{25}\)

\(d,\)\(\frac{4}{7}\)x \(\frac{2}{7}\)= \(\frac{8}{49}\)

Câu 8 :

\(a,\)\(\frac{5}{4}\)x \(x\)= \(\frac{3}{8}\)+ \(\frac{5}{12}\) 

           \(\frac{5}{4}\)x \(x\)= \(\frac{19}{24}\)

                       \(x\)= \(\frac{19}{24}\)\(:\)\(\frac{5}{4}\)

                      \(x\)= \(\frac{19}{30}\)

\(b,\)\(3\)x \(\frac{7}{10}\)+ \(\frac{7}{10}\)x \(5\)+ \(2\)x \(\frac{7}{10}\)

= \(\frac{7}{10}\)x \(\left(3+5+2\right)\)

= \(\frac{7}{10}\)x      \(10\)

= \(7\)

                                        #Học tốt#