计算如图所示阴影部分的周长或面积．
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%=
直接写出得数．﹣=12﹣0.12= 5.8+8= 48+32= 32= 0÷= 4÷4%= 0.6×0.5= ×=+=1÷=+5= ．
+= 24×= 5﹣=÷= 40×=×0.5= 0.4÷=﹣=÷0.4=+=
+
×
8.4÷0.7 470﹣72﹣28 5÷
+
×
×
×25% 698﹣299．
=
﹣
= 4.8÷12=
= 3.9×5×
+1﹣
﹣
= 2.25×4= 0.67+0.33=
÷
=
×80%=（
）×12= 45%÷15%=
﹣
=12﹣0.12= 5.8+8= 48+32= 
= 4÷4%= 0.6×0.5= 
×
=
+
=1÷
=
+5= ．
+
= 24×
= 5﹣
=
÷
= 40×
=
=
﹣
=
÷0.4=
+
=
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