45+99=
81-90=
40+60=
20-10=
50+06=
80-70=
30+40=
100-50=
700+700=
490-46=
50-67=
400+500=
600-513=
250+61=
900-999=
809+231=
709-490=
802+506=
401-501=
481+400=
456-121=
201+601=
700-234=
Mathbot Says...
I wasn't able to parse your question, but the HE.NET team is hard at work making me smarter.