题目内容
计算：39
×18
=______
______．
| 18 |
| 19 |
| 19 |
| 20 |
| 287661 |
| 380 |
39
×18
，
=
×
，
=（40-
）×（19-
），
=40×19-40×
-19×
+
×
，
=760-2-1+
，
=757
；
故答案为：757
．
| 18 |
| 19 |
| 19 |
| 20 |
=
| 18+39×19 |
| 19 |
| 19+18×20 |
| 20 |
=（40-
| 1 |
| 19 |
| 1 |
| 20 |
=40×19-40×
| 1 |
| 20 |
| 1 |
| 19 |
| 1 |
| 19 |
| 1 |
| 20 |
=760-2-1+
| 1 |
| 380 |
=757
| 1 |
| 380 |
故答案为：757
| 1 |
| 380 |
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