x=222...2⏟25=2.1024+2.1023+2.1022+...+2=2(1024+10223+...+1) benzer olarak y=444...4⏟25=4.1024+4.1023+4.1022+...+4=4(1024+10223+...+1) dır.
x.y=8(1024+10223+...+1).(1024+10223+...+1)
=8(1.1048+2.1047+3.1046+4.1045+...+24.1025+23.1024+22.1023+...+2.10+1)