用竖式计算17×243= 308×65= 450×60=
口算．﹣= += 2﹣= +=﹣= ﹣= ++= 1﹣﹣=﹣+= 5﹣﹣=
直接写得数.7.2÷9= ﹣= += ﹣+= 5﹣= ﹣×0=
= ．
直接写得数．= = = == = = =
﹣．
﹣
= 
+
= 2﹣
= 
+
=
﹣
= 
﹣
= 
+
+
= 1﹣
=
﹣
+
﹣
=
﹣
= 
+
= 
﹣
+
= 5﹣
= 
﹣
= ．
= 
= 
= 
=
= 
= 
= 
=
﹣
．
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