Question

巧算（1+1/2）X（1-1/2)X(1+1/3)X(1-1/3)X(1+1/4)X(1-1/4);1又1/4X64+12.5X3又1/2+1除以4/5

Answer 1

（1+1/2）X（1-1/2)X(1+1/3)X(1-1/3)X(1+1/4)X(1-1/4);
=3/2*1/2*4/3*2/3*5/4*3/4
=5/8

1又1/4X64+12.5X3又1/2+1除以4/5
=1.25×64+12.5×3.5+1×5/4
=1.25×（64+35+1）
=1.25×100
=125

Answer 2

（1+1/2）X（1-1/2)X(1+1/3)X(1-1/3)X(1+1/4)X(1-1/4)
=[（1+1/2）X（1-1/2)[X[(1+1/3)X(1-1/3)]X[(1+1/4)X(1-1/4)]
=(1-1/4)(1-1/9)(1-1/16)
=(3/4)(8/9)(15/16)
=5/8

1又1/4X64+12.5X3又1/2+1除以4/5
=(5/4)*64+(25/2)*(7/2)+1*(5/4)
=80+(175/4+5/4)
=80+45
=125