1.(1)+1.4 +1.2 -2.5 (2)-20 -5 -3
2.解:(1)(+15)+(-30)-(-14)=(+15)+(-30)+(+14)=+15+14-30=-1.
(2)-40-28-(-19)+(-24)=-40-28+19-24=-73.
(3)-2/3+(-1/6)-(-1/4)-1/2=-2/3-1/6+1/4-1/2=-8/12-2/12+3/12-6/12=-13/12=-1 1/12.
(4)-7.2-0.9-5.6+8.7=-13.7+8.7=-5.
(5)-1+2-3-4+5=-1.
(6)-3-4+19-11=1.
3.解:假设取出为负,存入为正,根据题意,得80+(-20)+(-30)+(+100)+ (-20)=110(元).
4.解:(1)如下表所示.
(2)5号队员最高,13号队员最矮.(3)(+5)-(-5)=(+5)+5=10(cm),或180-170=10(cm).