Hướng dẫn giải:
Bài `1:`
`a,1 1/10xx1 1/11xx1 1/12xx1 1/13xx1 1/14xx1 1/15xx1 1/16`
`=11/10xx12/11xx13/12xx14/13xx15/14xx16/15xx17/16`
`=(11xx12xx13xx14xx15xx16xx17)/(10xx11xx12xx13xx14xx15xx16)`
`=17/10=1,7`
`b,1 1/3xx2 1/4 xx3 1/5xx4 1/6xx5 1/7xx6 1/8xx7 1/9xx8 1/10`
`=4/3xx9/4xx16/5xx25/6xx36/7xx49/8xx64/9xx81/10`
`=(4xx9xx16xx25xx36xx49xx64xx81)/(3xx4xx5xx6xx7xx8xx9xx10)`
`=(4xx3xx3xx4xx4xx5xx5xx6xx6xx7xx7xx8xx8xx9xx9)/(3xx4xx5xx6xx7xx8xx9xx10)`
`=(4xx(3xx4xx5xx6xx7xx8xx9)xx(3xx4xx5xx6xx7xx8xx9))/(3xx4xx5xx6xx7xx8xx9xx10)`
`=(2xx2xx5xx(3xx4xx5xx6xx7xx8xx9)xx(3xx4xx6xx7xx8xx9))/(3xx4xx5xx6xx7xx8xx9xx10)`
`=((3xx4xx5xx6xx7xx8xx9xx10)xx(2xx3xx4xx6xx7xx8xx9))/(3xx4xx5xx6xx7xx8xx9xx10)`
`=2xx3xx4xx6xx7xx8xx9`
`=72576`
Bài `2:`
`5/4xx1,96-0,25xx1,96`
`=1,96xx(5/4-0,25)`
`=1,96xx1`
`=1,96`