2^100-2^99-2^98````-2
=(2^99*2)-2^99-2^98````-2
=(2^98*2)-2^98````-2
=2^2-2
=2
2^100可以看做是2^99在乘2,由此可得,减到后面就剩下2^2-2=2不知道这样你是否明白?`````