3.4+3.4+3.4+3.4+3.4=3.4× = .
÷8=0.75=27: = %
比就是分数. .
÷ = : =6:10== %.可见,除法、比、分数它们是有 的.
12÷ = :20=0.6= %=.
:20=4: =0.8== %