Ответы и объяснения

2014-02-05T15:54:43+04:00
2014-02-05T15:55:18+04:00
25/30- 20/60+15/30=50/60-20/60+30/60=30/60+30/60=60/60=1
 9/36+36/72-1/9=18/72+36/72-8/72=54/72-8/72=46/72=23/36