请问：速算（巧算）...请阅题：第一题：1/16+1/32+1/64+1/128=?第二题：1/2+1/6+1/12+1

(1) 1/16+1/32+1/64+1/128=2(1/16+1/32+1/64+1/128)-(1/16+1/32+1/64+1/128)
=1/8+1/16+32+1/64-(1/16+1/32+1/64+1/128=1/8-1/128=16/128-1/128=15/128
(2)1/2+1/6+1/12+1/20+1/30+1/42+1/56
=1/(1*2)+1/(2*3)+1/(3*4)+1/(4*5)+1/(5*6)+1/(6*7)+1/(7*8)
=1-1/2+1/2-1/3+1/3-1/4+1/4-1/5+1/5-1/6+1/6-1/7+1/7-1/8
=1-1/8=7/8
(3)1+2又1/6+3又1/12+4又1/20++5又1/30+6又1/42+7又1/56+8又1/72+9又1/90
=1+2+3+4+5+6+7+8+9+1/2-1/3+1/3-1/4+1/4-1/5+1/5-1/61/6-1/7+1/7-1/8+1/8-1/9+1/9-1/10=45+1/2-1/10=45又2/5