`3/4+ 2/3= 9/12+8/12=17/12`
`3/5+ 7/10=30/50 + 35/50= 65/50=13/10`
`1/4+7/6=6/24+ 28/24= 34/24=17/12`
`2/3-2/7=14/21-6/21= 8/21`
`3/4-5/12=9/12-5/12=4/12=1/3`
`5/6-2/9=45/54-12/54= 33/54`
`2+5/7=14/7+ 5/7=19/7`
`13/5-2=13/5-10/5=3/5`
`3-3/8= 24/8- 3/8= 21/8`
bn tách ra nhé!