1)1 2/9+ 1 7/12=11/9+19/12=(132+171)/108=303/108
2)303/108: 1 47/54 =303/108 : 101/54=303*54 / 108*101= 3/2
3)1 2/9 -1 7/12=11/2 - 19/12=(132-171)/108= -39/108
4)-39/108 : 5 7/13= -39/108: 72/13= -39*13 / 108*72=- 507/7776
5)3/2 -(-507/7776)=3/2 +507/7776= 1 3888/7776+ 507/7776=1 4395/7776=1 1465/2592