4.
a.
2/3
= 2 x 5 x 6/3 x 5 x 6 = 60/90
4/5
= 4 x 3 x 6/5 x 3 x 6 = 72/90
7/6
= 7 x 5 x 3/5 x 3 x 6 = 105/90
Vậy quy đồng mẫu ba phân số 2/3; 4/5; 7/6 ta đc: 60/90; 72/90; 105/90
b.
5/6
= 5 x 12 x 4/6 x 12 x 4 = 240/288
11/12
= 11 x 6 x 4/12 x 6 x 4 = 264/288
3/4
= 4 x 6 x 12/4 x 6 x 12 = 288/288
c.
7/8
= 7 x 12 x 18/8 x 12 x 18 = 1512/1728
5/12
= 5 x 8 x 18/8 x 12 x 18 = 720/1728
11/18
= 11 x 12 x 8/8 x 12 x 18 = 1056/1728
5.
a.
12/18 = 2/3
135/513 = 5/19
36/42 = 6/7
1212/1515 = 4/5
b.
4/7 < 7/4
15/17 > 15/19
9/8 < 5/4
35/42 = 55/66
~ xin ctlhn ạ! ~
