400-1=(200+200)-1=200-(200-1)=399
700-3=(500+200)-3=500+(200-3)=696
1000-5=(500+500)-5=500+(500-5)=995
500-2 =(300+200)-2=300+(200-2)=498
1000-10=(500+500)-10=500+(500-10)=990
2300-9=(500+1800)-9=500+(1800-9)=2291
800-30=(500+300)-30=500+(300-30)=770
1000-40=(500+500)-40=500+(500-40)=960
3500-10 =(500+3000)-10=500+(3000-10)=3490
210-12=(150+60)-12=150+(60-12)=198580-74 =(500+80)-74=500+(80-74)=506
1000-25=(500+500)-25=500-(500-25)=975