+x= x-(+)=1 -x=
3.56+65.4= 30-4.06= 0.05×0.6= 8.9-1.5÷0.3=
64×l.25= 4-0.02= 7.3÷0.01=
计算过程:
1800-799= ×0= 354+147≈
10-10%= 3.6 +1.8= ×5.6= 723÷89≈
2÷= 12.3+7 = 0.23= 0.125×17×8=