用简便方法计算:4.72+1.94+4.28+1.06 10.5-4.

问题描述:

用简便方法计算:4.72+1.94+4.28+1.06 10.5-4.
用简便方法计算:4.72+1.94+4.28+1.06 10.5-4.55-3.45

(4.72+4.28)+(1.94+1.06)10.5-(4.55+3.45)谢^_^)Y