(102)5=(100+2)5
Using binomial theorem, we have
(100+2)5=5C0(100)5+5C1(100)4(2)+5C2(100)3(2)2 +5C3(100)2(2)3+5C4(100)(2)4+5C5(2)5
=(100)5+5(100)4(2)+10(100)3(2)2+10(100)2(2)3+5(100)(2)4+(2)5
=10000000000+1000000000+40000000+ 800000+8000+32
=11040808032