求阴影部分的面积．
直接写出得数．
+
=
﹣
=
×2=
×
= 54﹣54×0=
×
=
÷4=÷
=
÷42= 0÷25+2.5=
×
=
×14=
÷4=
+÷
+=
直接写出得数．
3﹣2
= 1÷
= 321﹣178+257=
0.875÷
= 409×10﹣409= 2.25+7=
（
+）×18= 3
+2.7+2
+1.3=
口算、心算我最强
+
×
8.4÷0.7 470﹣72﹣28 5÷
﹣
+÷+
×
×
×25% 698﹣299．
直接写出得数．
28+43= 4﹣1.5= 2.5×4= 23.4÷10=
1.5+6﹣1.5= 1﹣
=
﹣
= 4.8÷12=÷
= 3.9×5×=
直接写得数．
1﹣
+1﹣=
﹣
= 2.25×4= 0.67+0.33=
÷
=
×80%=（+
）×12= 45%÷15%=