题目内容
用递等式计算.
①28.49÷7.4×0.32;
②(5
÷1.25+1
)×
-0.975;
③(0.2+
)÷
÷0.6;
④[(6
-0.45)÷1
]÷(1
÷6).
①28.49÷7.4×0.32;
②(5
1 |
4 |
1 |
2 |
1 |
3 |
③(0.2+
1 |
3 |
2 |
3 |
④[(6
1 |
5 |
5 |
18 |
1 |
3 |
考点:整数、分数、小数、百分数四则混合运算
专题:运算顺序及法则
分析:①按从左到右的顺序计算即可;
②先算小括号内的除法、加法,再算括号外的乘法、减法;
③先算小括号内的加法,再把除法转化为乘法约分计算;
④先算小括号内的,再算中括号内的除法,最后算括号外的除法.
②先算小括号内的除法、加法,再算括号外的乘法、减法;
③先算小括号内的加法,再把除法转化为乘法约分计算;
④先算小括号内的,再算中括号内的除法,最后算括号外的除法.
解答:
解:①28.49÷7.4×0.32
=3.85×0.32
=1.232;
②(5
÷1.25+1
)×
-0.975
=(4.2+1.5)×
-0.975
=5.7×
-0.975
=1.9-0.975
=0.925;
③(0.2+
)÷
÷0.6
=
×
×
=
;
④[(6
-0.45)÷1
]÷(1
÷6)
=[
÷1
]÷
=
×
=
.
=3.85×0.32
=1.232;
②(5
1 |
4 |
1 |
2 |
1 |
3 |
=(4.2+1.5)×
1 |
3 |
=5.7×
1 |
3 |
=1.9-0.975
=0.925;
③(0.2+
1 |
3 |
2 |
3 |
=
8 |
15 |
3 |
2 |
5 |
3 |
=
4 |
3 |
④[(6
1 |
5 |
5 |
18 |
1 |
3 |
=[
23 |
4 |
5 |
18 |
2 |
9 |
=
9 |
2 |
9 |
2 |
=
81 |
4 |
点评:此题考查了四则混合运算,注意运算顺序和运算法则.
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