(1)4.6-(1.42+2.07)
=4.6-3.49
=1.11;
(2)4.32-(1.26+2.34)
=4.32-3.6
=0.72;
(3)3.6-1.28+3.09
=2.32+3.09
=5.41;
(4)20-3.65+2.54
=16.35+2.54
=18.89;
(5)3.2+1.73-2.8
=4.93-2.8
=2.13;
(6)18.7+3.14-7.47
=21.84-7.47
=14.37;
(7)3.78+4.86+0.78
=8.64+0.78
=9.42;
(8)8.6+4.75-7.47
=13.35-7.47
=5.88;
(9)23.5-2.8+4.75
=20.7+4.75
=25.45.