Tính rồi rút gọn : 1.1/3 + 1/6 + 1/18 2.1/2 + 3/4 + 5/8 3.2/5 + 3/10 + 3/20 4.1/2 + 2/3 + 3/4 5.1/4 + 1/6 + 1/8 6.1/3 + 2/5 + 3/7 7.1 + 5/3 + 3/7 8.1/4 + 2 + 1/23 9.1/2 + 1/5 + 1/10 10.1/21 + 7/3 + 3/7 11.1/4 + 2/5 + 3/20 12.4/11 + 3/22 + 5/33 Bạn nào làm nhanh nhất tớ cho ctrlhn nha ! :3

`1) 1/3 + 1/6 + 1/18`

`= 6/18 + 3/18 +1/18`

`=10/18 =5/9`

`2) 1/2 + 3/4 + 5/8`

`= 4/8+6/8+5/8`

`=15/8`

`3) 2/5 + 3/10 + 3/20`

`= 8/20+6/20+3/20`

`=17/20`

`4) 1/2 + 2/3 + 3/4`

`= 6/12+8/12+9/12`

`= 23/12`

`5) 1/4 + 1/6 + 1/8`

`= 6/24+4/24+3/24`

`=13/24`

`6) 1/3 + 2/5 + 3/7`

`= 35/105 + 42/105 + 45/105`

`= 122/105 =19/15`

`7) 1 + 5/3 + 3/7`

`= 21/21 + 35/21 + 9/21`

`= 65/21`

`8) 1/4 + 2 + 1/23`

`= 23/92 + 184/92 + 4/92`

`= 211/92`

`9) 1/2 + 1/5 + 1/10`

`= 5/10 +2/10+1/10`

`=8/10=4/5`

`10) 1/21 + 7/3 + 3/7`

`= 1/21+49/21+9/21`

`=59/21`

`11) 1/4 + 2/5 + 3/20`

`= 5/20+8/20+3/20`

`=16/20=4/5`

`12) 4/11 + 3/22 + 5/33`

`=24/66+9/66+10/66`

`=43/66`