题目内容
用简便方法计算．
| 6.3×8.7+8.7×3.7 | （
|
|
分析：这三道题使用乘法分配律能使计算简便，由此解答即可．
解答：解：①6.3×8.7+8.7×3.7
=（6.3+3.7）×8.7
=10×8.7
=87；
②（
-
+
）×12
=
×12-
×12+
×12
=4-2+3
=5；
③
×
+
÷
．
=
×
+
×
=（
+
）×
=2×
=1
．
=（6.3+3.7）×8.7
=10×8.7
=87；
②（
| 1 |
| 3 |
| 1 |
| 6 |
| 1 |
| 4 |
=
| 1 |
| 3 |
| 1 |
| 6 |
| 1 |
| 4 |
=4-2+3
=5；
③
| 7 |
| 4 |
| 5 |
| 8 |
| 1 |
| 4 |
| 8 |
| 5 |
=
| 7 |
| 4 |
| 5 |
| 8 |
| 1 |
| 4 |
| 5 |
| 8 |
=（
| 7 |
| 4 |
| 1 |
| 4 |
| 5 |
| 8 |
=2×
| 5 |
| 8 |
=1
| 1 |
| 4 |
点评：此题主要考查运算定律的运用．
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