题目内容
脱式计算.
2+
|
|
8×6.5-148×0.65 | ||||||||||||||||||||||
|
|
|
分析:(1)先算减法,再算乘法,最后算加法;
(2)根据乘法分配律进行计算;
(3)根据乘法分配律进行计算;
(4)根据乘法分配律进行计算;
(5)先算小括号里面的乘法,再算中括号里面的除法,最后算括号外面的乘法;
(6)先算小括号里面的乘法,再算中括号里面的除法,最后算括号外面的乘法.
(2)根据乘法分配律进行计算;
(3)根据乘法分配律进行计算;
(4)根据乘法分配律进行计算;
(5)先算小括号里面的乘法,再算中括号里面的除法,最后算括号外面的乘法;
(6)先算小括号里面的乘法,再算中括号里面的除法,最后算括号外面的乘法.
解答:解:
(1)2+
×(0.6-0.25),
=2+
×0.35,
=2+0.28,
=2.28;
(2)
×
+
÷
,
=
×
+
×
,
=(
+
)×
,
=5×
,
=
;
(3)8×6.5-148×0.65,
=8×6.5-14.8×6.5,
=(8-14.8)×6.5,
=-6.8×6.5,
=-44.2;
(4)
×(
-
)+15%,
=
×
-
×
+15%,
=10-3+0.15,
=7+0.15,
=7.15;
(5)
×[
÷(
×
)],
=
×[
÷
],
=
×
,
=
;
(6)
×[
÷(
×
)],
=
×[
÷
],
=
×
,
=
.
(1)2+
4 |
5 |
=2+
4 |
5 |
=2+0.28,
=2.28;
(2)
11 |
8 |
5 |
9 |
29 |
8 |
9 |
5 |
=
11 |
8 |
5 |
9 |
29 |
8 |
5 |
9 |
=(
11 |
8 |
29 |
8 |
5 |
9 |
=5×
5 |
9 |
=
25 |
9 |
(3)8×6.5-148×0.65,
=8×6.5-14.8×6.5,
=(8-14.8)×6.5,
=-6.8×6.5,
=-44.2;
(4)
15 |
4 |
8 |
3 |
4 |
5 |
=
15 |
4 |
8 |
3 |
15 |
4 |
4 |
5 |
=10-3+0.15,
=7+0.15,
=7.15;
(5)
1 |
8 |
3 |
4 |
3 |
5 |
10 |
9 |
=
1 |
8 |
3 |
4 |
2 |
3 |
=
1 |
8 |
9 |
8 |
=
9 |
64 |
(6)
1 |
8 |
3 |
4 |
3 |
5 |
10 |
9 |
=
1 |
8 |
3 |
4 |
2 |
3 |
=
1 |
8 |
9 |
8 |
=
9 |
64 |
点评:四则运算,先弄清运算顺序,然后再进一步计算,能简算的要简算.
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