4.5元2.1元+2.4元                    4.6+3.15.8+2.7

3.6米7.7米-4.2米                     9.9-3.38.8-4.4

2吨+2.6吨0.3吨+3.7吨            7.9-4.88.3-3.6

0.1+0.1=          0.2+0.8=          4.6-0.6=          7.8-2.5=

3+0.7=             0.3+0.6=          7.2-0.2=          3.7-1.5=