Làm hộ em với ạ.

Câu `2`

`16/32 = {16 : 16}/{32 : 16} = 1/2`

Chọn `A`

Câu `3`

`12/48 = 1/4`

`1/4 = {1 × 3}/{4 × 3} = 3/12`

Chọn `C`

Câu `4`

`1/4 = {1 × 3}/{4 × 3} = 3/12`

`1/3 = {1 × 4}/{3 × 4} = 4/12`

Chọn `B`

Câu `5`

Chọn `C`

Bài `1`

`8/12 = {8 : 4}/{12 : 4} = 2/3`

`9/12 = {9 : 3}/{12 : 3} = 3/4`

`72/48 = {72 : 24}/{48 : 24} = 3/2`

`321/126 = {321 : 3}/{126 : 3} = 107/42`

`75/225 = {75 : 75}/{225 : 75} = 1/3`

`23/46 = {23 : 23}/{46 : 23} = 1/2`

Bài `2`

`a ) 1/2 = {1 × 500}/{2 × 500} = 500/1000`

`12/8 = {12 × 125}/{8 × 125} = 1500/1000`

`24/100 = {24 × 10}/{100 × 10} = 240/1000`

`b ) 5/8 = {5 × 70}/{8 × 70} = 350/560`

`144/28 = {144 × 20}/{28 × 20} = 2880/560`

`1212/1515 = 3/5 = {3 × 112}/{5 × 112} = 336/560`

Bài `3`

`a ) 1/2 > 1/12`

`b ) 5/7 > 5/9`

`c ) 2/3 = 8/12`

`3/4 = 9/12`

`8/12 < 9/12 => 2/3 < 3/4`

`d ) 8/9 = 64/72`

`7/8 = 63/72`

`64/72 > 63/72 => 8/9 > 7/8`

`#dtkc`