60005+(36006-28097)=60005+7909=67914
100105-(87007-679)=100105-86328=13777
400+80:4*5=400+100=500
800-640:2:4=800-80=720
60005+(36006-28097)=60005+7909=67914
100105-(87007-679)=100105-86328=13777
400+80:4*5=400+100=500
800-640:2:4=800-80=720