题目内容
(2011?苏州模拟)计算.(能简便的就用简便方法计算)
①25×10.4-1068÷89
②57.5-14.25-15
③34.5×9.23+0.77×34.5
④64×1.25×2.5×5
⑤(
+
)÷(2-1
)
⑥(
+
)÷
+
.
①25×10.4-1068÷89
②57.5-14.25-15
3 |
4 |
③34.5×9.23+0.77×34.5
④64×1.25×2.5×5
⑤(
1 |
3 |
3 |
4 |
1 |
2 |
⑥(
4 |
5 |
1 |
4 |
7 |
3 |
7 |
10 |
分析:算式①可将式中25×10.4据乘法分配律变为25×(10+0.4)进行计算;
算式②可将式中分数化为小数后据减法性质进行计算;
算式③可据乘法分配律进行计算;
算式④可将64拆分为8×4×2后再据乘法交换律及结合律计算;
算式⑤、⑥根据四则混合运算的运算顺序计算即可.
算式②可将式中分数化为小数后据减法性质进行计算;
算式③可据乘法分配律进行计算;
算式④可将64拆分为8×4×2后再据乘法交换律及结合律计算;
算式⑤、⑥根据四则混合运算的运算顺序计算即可.
解答:解:①25×10.4-1068÷89
=25×(10+0.4)-1068÷89,
=25×10+25×0.4-12,
=250+10-12,
=248;
②57.5-14.25-15
=57.5-14.25-15.75,
=57.5-(14.25+15.75),
=57.5-30,
=27.5;
③34.5×9.23+0.77×34.5
=(9.23+0.77)×34.5,
=10×34.5,
=345;
④64×1.25×2.5×5
=8×4×2×1.25×2.5×5,
=(1.25×8)×(2.5×4)×(5×2),
=10×10×10,
=1000;
⑤(
+
)÷(2-1
)
=
÷
,
=
;
⑥(
+
)÷
+
=
×
+
,
=
+
,
=
.
=25×(10+0.4)-1068÷89,
=25×10+25×0.4-12,
=250+10-12,
=248;
②57.5-14.25-15
3 |
4 |
=57.5-14.25-15.75,
=57.5-(14.25+15.75),
=57.5-30,
=27.5;
③34.5×9.23+0.77×34.5
=(9.23+0.77)×34.5,
=10×34.5,
=345;
④64×1.25×2.5×5
=8×4×2×1.25×2.5×5,
=(1.25×8)×(2.5×4)×(5×2),
=10×10×10,
=1000;
⑤(
1 |
3 |
3 |
4 |
1 |
2 |
=
13 |
12 |
1 |
2 |
=
13 |
6 |
⑥(
4 |
5 |
1 |
4 |
7 |
3 |
7 |
10 |
=
21 |
20 |
3 |
7 |
7 |
10 |
=
9 |
20 |
7 |
10 |
=
23 |
20 |
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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