用[x]表示小于x的整数部分,例如[13.52]=13,若x=8.28,则[x]+[2x]+[3x]+[4x]= .
30÷12==5: = :6= (小数)
÷16== : == [最后一个空填小数].
0.6==12÷ = : = %
: ==12: = %
:16=9: =0.75= %