5•a•b= 98+17= 103×40= 7b十5b=1000÷125= 90×70= n×n= 37十68×0=380+320= y+y= 56×78×0= 25×14﹣25×10=
3÷﹣÷3．
18×+12×0.25+10×25%
+6.28+﹣4.28．
神机妙算细又巧！（写出简算过程）×9+（+）×15×17×12﹣÷×+×+．
×3.6+×0.75．
﹣
÷3．
+12×0.25+10×25%
+6.28+
﹣4.28．
×9+
（
+
）×15×17
×12﹣
×
+
×
×3.6+
×0.75．
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