题目内容
(2013?东莞模拟)正确、合理、灵活的计算下面各题.
①(1.75×0.2+1.75×0.8)÷0.175
②10
-(6
-2
)
③243×8
+75.7×82.5
④
×1
+125%+0.625×1.25
⑤0.91÷
+1.25×1.09
⑥(
+
-
)÷
.
①(1.75×0.2+1.75×0.8)÷0.175
②10
1 |
4 |
1 |
4 |
1 |
5 |
③243×8
1 |
4 |
④
3 |
8 |
1 |
4 |
⑤0.91÷
4 |
5 |
⑥(
5 |
6 |
7 |
8 |
5 |
12 |
1 |
24 |
分析:算式①③④⑤⑥都是运用乘法的分配律进行计算,使计算更加简便.
算式②运用一个数减去两个数的差,可以用这个数减去被减数加上减数.
算式②运用一个数减去两个数的差,可以用这个数减去被减数加上减数.
解答:解:①(1.75×0.2+1.75×0.8)÷0.175,
=1.75×(0.2+0.8)÷0.175,
=1.75÷0.175,
=10;
②10
-(6
-2
),
=10.25-6.25+2.2,
=4+2.2,
=6.2;
③243×8
+75.7×82.5,
=243×8.25+757×8.25,
=8.25×(243+757),
=8.25×1000,
=8250;
④
×1
+125%+0.625×1.25,
=0.375×1.25+0.625×1.25,
=1.25×(0.375+0.625),
=1.25×1,
=1.25;
⑤0.91÷
+1.25×1.09,
=0.91×1.25+1.25×1.09,
=1.25×(0.91+1.09),
=1.25×2,
=2.5;
⑥(
+
-
)÷
,
=(
+
-
)×24,
=24×
+24×
-24×
,
=20+21-10,
=31.
=1.75×(0.2+0.8)÷0.175,
=1.75÷0.175,
=10;
②10
1 |
4 |
1 |
4 |
1 |
5 |
=10.25-6.25+2.2,
=4+2.2,
=6.2;
③243×8
1 |
4 |
=243×8.25+757×8.25,
=8.25×(243+757),
=8.25×1000,
=8250;
④
3 |
8 |
1 |
4 |
=0.375×1.25+0.625×1.25,
=1.25×(0.375+0.625),
=1.25×1,
=1.25;
⑤0.91÷
4 |
5 |
=0.91×1.25+1.25×1.09,
=1.25×(0.91+1.09),
=1.25×2,
=2.5;
⑥(
5 |
6 |
7 |
8 |
5 |
12 |
1 |
24 |
=(
5 |
6 |
7 |
8 |
5 |
12 |
=24×
5 |
6 |
7 |
8 |
5 |
12 |
=20+21-10,
=31.
点评:本题主要考查了学生能否根据数字的特点,选择运用乘法的分配律进行计算,运用运算定律使计算更加简便.
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