1) I-106I+I-8,2I·I- 25/41I=106+82/10 · 25/41=106+5=111
2) I-1I+I-0,85I· 16/17=1+85/100 · 16/17=1+4/5=1,8
3) I-55/81I:I-44/135I+I8 11/12I=55/81 · 135/44 +107/12=25/12 +107/12=132/12=11
4) I-2 2/7I-I303/400I:I707/800I=16/7 - 303/400 ·800/707=16/7-6/7=10/7