Giải thích các bước giải:
`7/9 xx 3/14 : 5/18`
`=7/9xx3/14xx18/5`
`=(7xx3xx18)/(9xx14xx5)`
`=(7xx3xx9xx2)/(9xx7xx2xx5)`
`=3/5`
`8/11 +8/33 xx 3/4`
`=8/11+(8xx3)/(33xx4)`
`=8/11+(2xx4xx3)/(11xx3xx4)`
`=8/11+2/11`
`=10/11`
`5/12 -7/32 : 21/16`
`=5/12-7/32xx16/21`
`=5/12-(7xx16)/(32xx21)`
`=5/12-(7xx8xx2)/(8xx2xx2xx7xx3)`
`=5/12-1/6`
`=5/12-2/12`
`=3/12`
`=1/4`