1/2+1/4+1/8+1/16+1/32+1/64+1/128
=1/128x64+1/128x32+1/128x16+1/128x8+1/128x4+1/128x2+1/128
=1/128x(64+32+16+8+4+2+1)
=1/128x127
=127/128
1/2+1/4+1/8+1/16+1/32+1/64+1/128
=1/128x64+1/128x32+1/128x16+1/128x8+1/128x4+1/128x2+1/128
=1/128x(64+32+16+8+4+2+1)
=1/128x127
=127/128