680L=dm3=m3
12/()=3÷4=()/12=15÷ =(填小数)
+ =
﹣ =
8﹣ =
0.84÷4=
0.6×5=
+ ﹣ ﹣ + ﹣( + ) + + + +( ﹣ ) ﹣ ﹣