写出各算式相对应的加法算式和减法算式。7+4=( )( )+( )=( )( )-( )=( )( )-( )=( )
6÷ =9:12== = %
1.25= :8== %.
2= : =27÷ =.
最小质数除以最小合数,商是,化成小数是 ;0.75=9÷ ==18÷ =.
== ÷ == (小数)