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简便计算．28.9-（3.5+18.9）；2.5×1.3×0.4；813÷9+19×513．
题目详情
简便计算．
28.9-（3.5+18.9）； 2.5×1.3×0.4；
÷9+
×
．简便计算．
28.9-（3.5+18.9）； 2.5×1.3×0.4；
÷9+
×
．
÷9+
×
．
8 13 8 8 13 13
×
．
1 9 1 1 9 9
．
5 13 5 5 13 13
28.9-（3.5+18.9）； 2.5×1.3×0.4；
| 8 |
| 13 |
| 1 |
| 9 |
| 5 |
| 13 |
28.9-（3.5+18.9）； 2.5×1.3×0.4；
| 8 |
| 13 |
| 1 |
| 9 |
| 5 |
| 13 |
| 8 |
| 13 |
| 1 |
| 9 |
| 5 |
| 13 |
| 8 |
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| 1 |
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▼优质解答
答案和解析
（1）28.9-（3.5+18.9）
=28.9-18.9-3.5
=10-3.5
=6.5
（2）2.5×1.3×0.4
=2.5×0.4×1.3
=1×1.3
=1.3
（3）
÷9+
×
=
×
+
×
=（
+
）×
=1×
=
8 13 8 8 813 13 13÷9+
×
=
×
+
×
=（
+
）×
=1×
=
1 9 1 1 19 9 9×
=
×
+
×
=（
+
）×
=1×
=
5 13 5 5 513 13 13
=
×
+
×
=（
+
）×
=1×
=
8 13 8 8 813 13 13×
+
×
=（
+
）×
=1×
=
1 9 1 1 19 9 9+
×
=（
+
）×
=1×
=
1 9 1 1 19 9 9×
=（
+
）×
=1×
=
5 13 5 5 513 13 13
=（
+
）×
=1×
=
8 13 8 8 813 13 13+
）×
=1×
=
5 13 5 5 513 13 13）×
=1×
=
1 9 1 1 19 9 9
=1×
=
1 9 1 1 19 9 9
=
1 9 1 1 19 9 9
=28.9-18.9-3.5
=10-3.5
=6.5
（2）2.5×1.3×0.4
=2.5×0.4×1.3
=1×1.3
=1.3
（3）
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