PAT (Advanced Level)1023 Have Fun with Numbers (20分)
Noticethatthenumber123456789isa9-digitnumberconsistingexactlythenumbersfrom1to9,withnoduplication.Doubleitwewillobtain246913578,whichhappenstobeanother9-digitnumberconsistingexactlythenumbersfrom1to9,