-= 20÷= 0.77+0.23= +2-+2=
0.3÷0.5= ×7.2= 4000÷80= 1.5×4+6=
301﹣199=
+ =
×16=
÷ =
2.1﹣1.2=
3.2+1.8=
× ÷ × =
40×25%=
①634﹣3.2×1.5÷0.1
②9.43+0.78﹣3.43
③
④
⑤
⑥