bai....................kho......................wa.....................troi.........................thi.................lanh...............lai....................mua...................tich....................ung.....................ho..................minh....................nha.......................huhu
a)15/24; 14/24
b)68/60; 87/60
a)5/8=15/24;7/12=14/24
b)17/15=68/60;29/20=87/60
Hok tốt