+= ﹣= 24×= 5﹣=
30÷= += +0.25= ÷=
0.22=
6.8+1.28=
0.5÷0.25=
50×30%=
1﹣1÷7=
6÷=
×24=
2008﹣199=
+=
2.5×0.7×0.4=