题目内容
怎样简便就怎样算
(12.5-0.125)×8; 5.25×
-0.75÷5; 253×102;
÷[(
+
)×15].
(12.5-0.125)×8; 5.25×
1 |
5 |
1 |
5 |
2 |
3 |
1 |
5 |
考点:运算定律与简便运算
专题:运算定律及简算
分析:①(12.5-0.125)×8,运用乘法分配律简算;
②5.25×
-0.75÷5,把除数转化为乘它的倒数,再运用乘法分配律简算;
③253×102,转化为:253×(100+2),运用乘法分配律简算;
④
÷[(
+
)×15],运用乘法分配律简算.
②5.25×
1 |
5 |
③253×102,转化为:253×(100+2),运用乘法分配律简算;
④
1 |
5 |
2 |
3 |
1 |
5 |
解答:
解:①(12.5-0.125)×8
=12.5×8-0.125×8
=100-1
=99;
②5.25×
-0.75÷5
=(5.25-0.75)×
=4.5×
=0.9;
③253×102
=253×100+253×2
=25300+506
=25806;
④
÷[(
+
)×15]
=
÷[
×15+
×15]
=
÷[10+3]
=
÷13
=
×
=
.
=12.5×8-0.125×8
=100-1
=99;
②5.25×
1 |
5 |
=(5.25-0.75)×
1 |
5 |
=4.5×
1 |
5 |
=0.9;
③253×102
=253×100+253×2
=25300+506
=25806;
④
1 |
5 |
2 |
3 |
1 |
5 |
=
1 |
5 |
2 |
3 |
1 |
5 |
=
1 |
5 |
=
1 |
5 |
=
1 |
5 |
1 |
13 |
=
1 |
65 |
点评:此题考查的目的是理解掌握整数、小数、分数四则混合运算的顺序以及它们的计算法则,并且能够灵活选择简算方法进行计算.
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