举例10.5-2.2=8.3 11-2.3=8.7 11.5-2.4=9.1 12-2.5=9.5 12.5-2.6=9.9 13-2.7=10.3 0.2+0.6+0.0.2=12.8 + 1.5 + 0.7=53.12- 5.6 + 2.9=0.424.8- 5.4 + 1.4 =0.85.6- 3.8 – 0.38 = 1.426.4 + 5.9 + 3.7 = 16
