Rút gọn các phân số về tối giản, ta được:
\(\dfrac{2}{5}\) (đã tối giản)
\(\dfrac{4}{16}=\dfrac{4:4}{16:4}=\dfrac{1}{4}\)
\(\dfrac{3}{5}\)(đã tối giản)
\(\dfrac{36}{72}=\dfrac{36:36}{72:36}=\dfrac{1}{2}\)
\(\dfrac{9}{27}=\dfrac{9:9}{27:9}=\dfrac{1}{3}\)
Quy đồng lên, ta được:
\(\dfrac{2}{5}=\dfrac{2\times24}{5\times24}=\dfrac{48}{120}\)
\(\dfrac{1}{4}=\dfrac{1\times30}{4\times30}=\dfrac{30}{120}\)
\(\dfrac{3}{5}=\dfrac{3\times24}{5\times24}=\dfrac{72}{120}\)
\(\dfrac{1}{2}=\dfrac{1\times60}{2\times60}=\dfrac{60}{120}\)
\(\dfrac{1}{3}=\dfrac{1\times40}{3\times40}=\dfrac{40}{120}\)
Mà \(\dfrac{72}{120}>\dfrac{60}{120}>\dfrac{48}{120}>\dfrac{40}{120}>\dfrac{30}{120}\)
Vậy ta sắp xếp được theo thứ tự giảm dần là \(\dfrac{3}{5};\dfrac{36}{72};\dfrac{2}{5};\dfrac{9}{27};\dfrac{4}{16}\).
rút gọn: 4/16= 4:4/16:4= 1/4
36/72= 36:36/72:36= 1/2
9/27= 9:9/27:9= 1/3
Nên: 2/5; 1/4; 3/5; 1/2; 1/3
MSC: 60
2/5= 2x12/5x12= 24/60
1/4= 1x15/4x15= 15/60
3/5= 3x12/5x12= 36/60
1/2= 1x30/ 2x30= 30/60
1/3= 1x20/3x20= 20/60
→36/60, 30/60, 24/60, 20/60, 15/60
Hay 3/5, 1/2, 1/3, 2/5, 1/4
Vậy 3/5> 36/72> 9/27> 2/5> 4/16
