题目内容
用递等式计算(怎样简便就怎样算).
①14760÷36-24×11;
②2.5×8×3.75×0.4;
③4
×7
+9.4×4.125-4
;
④(2
+1
)÷(1-
×
);
⑤(1
×2.2+2
×1.6)÷6
;
⑥[10-12×(0.5+
)]÷4
.
①14760÷36-24×11;
②2.5×8×3.75×0.4;
③4
1 |
8 |
3 |
5 |
1 |
8 |
④(2
1 |
4 |
5 |
6 |
3 |
4 |
2 |
5 |
⑤(1
3 |
5 |
4 |
5 |
2 |
5 |
⑥[10-12×(0.5+
1 |
3 |
4 |
5 |
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:①④⑥根据四则混合运算的运算顺序计算即可:先算乘除,再算加减,有括号的要先算括号里面的.
②可根据乘法交换律与结合律计算.
③可将式中的分数化成小数后,根据乘法分配律计算.
⑤可根据乘法分配律计算括号中的算式.
②可根据乘法交换律与结合律计算.
③可将式中的分数化成小数后,根据乘法分配律计算.
⑤可根据乘法分配律计算括号中的算式.
解答:
解:①14760÷36-24×11
=410-264
=146;
②2.5×8×3.75×0.4
=2.5×0.4×(8×3.75)
=1×30
=30;
③4
×7
+9.4×4.125-4
=4.125×7.6+9.4×4.125-4.125
=4.125×(7.6+9.4-1)
=4.125×16
=66;
④(2
+1
)÷(1-
×
)
=4
÷(1-
)
=
÷
=
;
⑤(1
×2.2+2
×1.6)÷6
=(1.6×2.2+2.8×1.6)÷6
=(2.2+2.8)×1.6÷6.4
=5×1.6÷6.4
=8÷6.4
=1.25
⑥[10-12×(0.5+
)]÷4
=[10-12×
]×
=[10-10]×
=0×
=0.
=410-264
=146;
②2.5×8×3.75×0.4
=2.5×0.4×(8×3.75)
=1×30
=30;
③4
1 |
8 |
3 |
5 |
1 |
8 |
=4.125×7.6+9.4×4.125-4.125
=4.125×(7.6+9.4-1)
=4.125×16
=66;
④(2
1 |
4 |
5 |
6 |
3 |
4 |
2 |
5 |
=4
1 |
12 |
3 |
10 |
=
49 |
12 |
7 |
10 |
=
35 |
6 |
⑤(1
3 |
5 |
4 |
5 |
2 |
5 |
=(1.6×2.2+2.8×1.6)÷6
2 |
5 |
=(2.2+2.8)×1.6÷6.4
=5×1.6÷6.4
=8÷6.4
=1.25
⑥[10-12×(0.5+
1 |
3 |
4 |
5 |
=[10-12×
5 |
6 |
5 |
24 |
=[10-10]×
5 |
24 |
=0×
5 |
24 |
=0.
点评:当算式中同时含有小括号与中括号时,要先算小括号里面的,再算中括号里面的.
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