题目内容
简便运算:
①7×13×(
-
)
②125÷(50÷8)
③13
-2.25-7
④9999×7+1111×37.
①7×13×(
| 4 |
| 7 |
| 2 |
| 13 |
②125÷(50÷8)
③13
| 2 |
| 3 |
| 3 |
| 4 |
④9999×7+1111×37.
分析:①根据数据的特点,运用乘法分配律简算即可;
②运用除法的性质,把原式变为125÷50×8,运用乘法交换律简算即可;
③运用减法的性质简算即可;
④把9999看作1111×9,原式变为1111×9×7+1111×37,运用乘法分配律的逆运算简算即可.
②运用除法的性质,把原式变为125÷50×8,运用乘法交换律简算即可;
③运用减法的性质简算即可;
④把9999看作1111×9,原式变为1111×9×7+1111×37,运用乘法分配律的逆运算简算即可.
解答:解:①7×13×(
-
),
=7×13×
-7×13×
,
=52-14,
=38;
②125÷(50÷8),
=125÷50×8,
=125×8÷50,
=1000÷50,
=20;
③13
-2.25-7
,
=13
-(2.25+7.75),
=13
-10,
=3
;
④9999×7+1111×37,
=1111×9×7+1111×37,
=1111×63+1111×37,
=1111×(63+37),
=1111×100,
=111100.
| 4 |
| 7 |
| 2 |
| 13 |
=7×13×
| 4 |
| 7 |
| 2 |
| 13 |
=52-14,
=38;
②125÷(50÷8),
=125÷50×8,
=125×8÷50,
=1000÷50,
=20;
③13
| 2 |
| 3 |
| 3 |
| 4 |
=13
| 2 |
| 3 |
=13
| 2 |
| 3 |
=3
| 2 |
| 3 |
④9999×7+1111×37,
=1111×9×7+1111×37,
=1111×63+1111×37,
=1111×(63+37),
=1111×100,
=111100.
点评:完成本题要注意分析式中数据,运用合适的简便方法计算.
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