-(9.8+6.9)-(10,2-6.9) б)(1.59+3.47)-(2.47+0.59) в)(1.9+2.5)-(5.9-2.5) г)(0.85+1.5)-(-0.65-3.5)

а) -(9.8+6.9)-(10,2-6.9)= -16,7-3,3=20

б) (1.59+3.47)-(2.47+0.59)= 5,06-3,06=2

в) (1.9+2.5)-(5.9-2.5) = 4,4-3,4=1

г) (0.85+1.5)-(-0.65-3.5) =2,35-(-4,15)=2,35+4,15=6,5