1)32+11+18+39 = (32+18)+(11+39)=50+50 = 100
2)45+21+15+49 = (45+15)+(21+49)=60+70 = 130
3)64+33+16+47 = (64+16)+(33+47)=70+80 = 150
4)56+25+45+24 = (56+24)+(25+45)=80+70 = 150
5)72+67+23+18 = (72+18)+(67+23)=90+90 = 180
6)97+42+58+103
= (97+103)+(42+58)=200+100 = 300