1) 352+(−431)−2157=3156−4155−2157=
=3156−61512=−3156=−352;
2) 2245−485−(−3125)+(−61)=
=2245−42415+32410−244=
=(2245+32410)−(42415+244)=
=52415−42419=42439−42419=2420=65
3) −241+3,7−2,9−(−352)=−2,25+3,7−2,9+3,4=
=(3,7+3,4)−(2,25+2,9)=7,1−5,15=1,95;
4) 4,9−7103−843−(−8,2)=4,9−7,3−8,75+8,2=
=(4,9+8,2)−(7,3+8,75)=13,1−16,05=−2,95.