递等式计算能桥算的就要算 3.9*1.4-0.4*30= 4.25-3.62+17.48= 5.68*（1.2-0.34）=
问题描述：
递等式计算能桥算的就要算 3.9*1.4-0.4*30= 4.25-3.62+17.48= 5.68*（1.2-0.34）=
递等式计算能巧算的就巧算 3.9*1.4-0.4*30= 4.25-3.62+17.48= 5.68*（1.2-0.34）=
答
3.9*1.4-0.4*30
=5.46-12
=-6.54
4.25-3.62+17.48
=0.63+17.48
=18.11
5.68*（1.2-0.34）
=5.68*0.86
=4.8848