（1）原式=990÷55-5

                =18-5

                =13（2）原式=（63+30）-29

                =93-29

                =64

（3）原式=63.64-（18.67+1.33）

                =63.64-20

                = 43.64（4）原式=29.38-19.38+4.76

                =10+4.76

                =14.76

（5）原式=13.67-2.97+25.8

                =10.7+25.8

                =36.5（6）原式=7.06+13.78-2.78

                =7.06+11

                =18.06