1又4分之1×8.08
=(1+1/4)×8.08
=1×8.08+1/4×8.08
=8.08+2.02
=10.10
101又99分之1×100分之1
=(100+1又1/99）×1/100
=100×1/100+100/99×1/100
=1+1/99
=1又1/99
6分之5+12分之5+20分之5+30分之5+42分之5
==5×(1/3-1/4+1/4-1/5+1/5-1/6+1/6-1/7)
=5×(1/3-1/7)
=5×4/21
=20/21
6667×2222+6666×1111
=6667×2222+3333×2×1111
=（6667+3333）×2222
=10000×2222
=22220000