Răspuns:
a) (420·5+31)-20·25 = (2100+31)-20·25=2131-500=1631
Ordinea efectuarii operatiilor:
1) 420·5 = 2100
2) 2100+31 = 2131
3) 20·25 = 500
4) 2131-500=1631
b) 1950-(27·25+40:4)= 1950-(675+10)=1950-685=1265
c) 39·400+[23+2·(23-2·3)]= 15600+[23+2·(23-6)]= 15600+(23+2·17)= 15600+(23+34)=15600+57= 15657
d) [(470·50-2·190)+70:10·19]-52= [(23500-380)+7·19]-52= (23120+133)-52= 23253-52= 23201
