口算．180÷2.5÷4= 1÷75%= += 1﹣+=÷= 7×8×（+）= ÷×0= 1﹣÷=
怎样简便怎样计算 ①+++ ②1﹣﹣ ③+（﹣） ④3﹣（+）
直接写得数．+=+=﹣=+= 1﹣+= 1﹣=﹣= 1﹣﹣= 4﹣﹣= 5﹣﹣=
直接写出得数．+=+=﹣= 15﹣=
========
口算高速直达.+=+= 0.32=+2=+﹣+=﹣0.25=+= 12.5×8= 2﹣﹣=﹣+=
+
= 1﹣
+
=
÷
= 7×8×（
+
）= 
÷
×0= 1﹣
÷
+
+
+
②1﹣
﹣
+（
﹣
） ④3﹣（
+
）
+
=
+
﹣
=
+
= 1﹣
+
=
=
﹣
= 1﹣
﹣
= 4﹣
﹣
= 5﹣
﹣
=
+
=
+
=
﹣
= 15﹣
=
=
=
=
=
=
=
=
=
+
=
+
= 0.32=
+2=
+
﹣
=
﹣0.25=
+
= 12.5×8= 2﹣
﹣
=
﹣
+
=
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