Question

[Tran Thu]

Quy đồng mẫu số rồi sắp xếp các phân số sau theo thứ tự tăng dần

a)-3/8; 11/24;11/18;-7/9;4/5 

b) -4/15;7/9;-1/3;2/5;0;13/45

Answer 1

[Nguyễn Thị Thương Hoài]

a; 8 = 2³; 24 = 2³.3; 18 = 2.3²; 5 = 5

 BCNN(8; 24; 18; 5) = 2³.3².5 = 360

\(\dfrac{-3}{8}\) = \(\dfrac{-3.45}{8.45}\) = \(\dfrac{-135}{360}\);  \(\dfrac{11}{24}\) =  \(\dfrac{11.15}{24.15}\) = \(\dfrac{165}{360}\) 

\(\dfrac{11}{18}\) = \(\dfrac{11.20}{18.20}\) = \(\dfrac{220}{360}\); \(\dfrac{-7}{9}\) = \(\dfrac{-7.40}{9.40}\) = \(\dfrac{-280}{360}\)

 \(\dfrac{4}{5}\) = \(\dfrac{4.72}{5.72}\) = \(\dfrac{288}{360}\); 

\(\dfrac{-7}{9}\); \(\dfrac{-3}{8}\); \(\dfrac{11}{24}\); \(\dfrac{11}{18}\); \(\dfrac{4}{5}\)

Answer 2

[Nguyễn Thị Thương Hoài]

b; 15 = 3.5; 9 = 3²; 3 = 3; 45 = 3².5

BCNN(15; 9; 45) = 3².5

\(\dfrac{-4}{15}\) = \(\dfrac{-4.3}{15.3}\) = \(\dfrac{-12}{45}\); \(\dfrac{7}{9}\) = \(\dfrac{7.5}{9.5}\) = \(\dfrac{35}{45}\); \(\dfrac{-1}{3}\) = \(\dfrac{-1.15}{3.15}\) = \(\dfrac{-15}{45}\)

\(\dfrac{2}{5}\) = \(\dfrac{2.9}{5.9}\) =  \(\dfrac{18}{45}\); 0 = \(\dfrac{0}{45}\); \(\dfrac{13}{45}\)

\(\dfrac{-1}{3}\); \(\dfrac{-4}{15}\); 0; \(\dfrac{13}{45}\); \(\dfrac{2}{5}\);  \(\dfrac{7}{9}\)