7/15-5/3=-18/15 43/8*(-18/15)=-6.45 2*2.8=5.6
-6.45+5.6=-0.85
C=2пR
C=2*3,14*19,79
C=124,2812...
C=124,28
1.28/35=4/5
44/88=1/2
196/84=7/3
2. 11/12>13/16
17/48>25/72
3) 38,6*1,8+1,8*2,7=18(38,6+2,7)=18*41,3=743,4
4) 10,27*5,1+18,3*5,1=5,1(10,27+18,3)=5,1*28,57=145,7
5) 2,3(9,5-7,2)=2,3*2,3=5,29
6)0,4(5,1+6,9)=0,4*12=4,8