1). 7 2/7-4 5/14=7 4/14-4 5/14=6 18/14- 4 5/14=2 13/14
2). 8 13/20-5 27/40= 8 26/40-5 27/40=7 66/40-5 27/40=2 39/40
3). 12 11/18-5 25/2=12 11/18-17 1/2=12 11/18-17 9/18=12 11/18-16 27/18=-4 6/18=-4 1/3
т.к. 25/2=12 1/2
4). 15 4/9-9 17/18=15 8/18-9 17/18=14 26/18-9 17/18=5 9/18=5 1/2
5). 30 37/44-24 21/22=30 37/44-24 42/44=29 81/44-24 42/44=5 39/44
6). 42 21/26-28 11/13=42 21/26-28 22/26=41 47/26- 28 22/26=13 25/26