(-2.5)-(+4.2)+(-3.5)-(+2.8)用加法运算律计算
问题描述:
(-2.5)-(+4.2)+(-3.5)-(+2.8)用加法运算律计算
答
(-2.5)-(+4.2)+(-3.5)-(+2.8)
=[(-2.5)+(-3.5)]+[(-4.2)+(-2.8)]
=[-6]+[-7]
=-13