先估计商是几位数，再列竖式计算并验算．432÷4 586÷7 643÷8．
用简便方法计算． 3892﹣2998= 23﹣2﹣7=4×5﹣4×4.375=
用简便方法计算 ①8.36﹣0.75﹣②99+992③×25+×10．
简算 ①56×（﹣+）②32×1.25×0.25 ③78.9×99+78.9④57.2﹣0.4﹣11.6．
脱式计算，能简算的要简算 9.81×0.1+0.5×98.1+0.049×9812÷[（2﹣1.2）×+0.05] 100﹣32×0.125×0.25 [1﹣（﹣）]×．
用简便方法计算（写出简算过程） ①（++）×12②18.93﹣6﹣3 ③163×﹣0.75×62﹣75%④7÷+1×2．
﹣7
=4
×5
﹣4
×4.375=
②99+992③
×25+
×10．
﹣
+
）②32×1.25×0.25 ③78.9×99+78.9④57.2﹣0.4﹣11.6．
÷[（2
﹣1.2）×
+0.05]
﹣
）]×
．÷[（2﹣1.2）×+0.05]﹣）]×．
+
+
）×12②18.93﹣6
﹣3
﹣0.75×62﹣75%④7
÷
+1
×2
．
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