abcde=a.10000+b.1000+c.100+d.10+c.1
=a.104+b.103+c.102+d.101+e.100
abcde=a.10^4+b.10^3+c.10^2+d.10^1+e.10...
Ta có:abcde
=104.a+103.b+102.c+101.d+100.e
Vậy
abcde = 10000a + 1000b + 100c + 10d + e
= 104a + 103b + 102c + 101d + 100e
abcde = a.104 + b.103 + c.102 + d.10 + e