题目内容
| 9.63-7.52-2.49+0.43 | 2000-1998+1996-1994+…-6+4-2 | ||||||||||||||||||
|
[1-(
|
分析:(1)运用加法交换律与结合律以及减法的性质简算;
(2)通过观察,发现2000-1998=2,1996-19942,…,4-2=2,共有2000÷2÷2=500组,即500个2,计算即可;
(3)原式变为
×(0.375×12.4+1+1.1×
)-
,先算括号内的乘法,再算括号内的加法,然后算括号外的乘法,最后算减法;
(4)先算小括号内的繁分式,再算加法;然后算中括号内的乘法,再算中括号内的减法,最后算括号外的除法.
(2)通过观察,发现2000-1998=2,1996-19942,…,4-2=2,共有2000÷2÷2=500组,即500个2,计算即可;
(3)原式变为
| 2 |
| 3 |
| 7 |
| 2 |
| 1 |
| 4 |
(4)先算小括号内的繁分式,再算加法;然后算中括号内的乘法,再算中括号内的减法,最后算括号外的除法.
解答:解:(1)9.63-7.52-2.49+0.43,
=(9.63+0.43)-(7.52+2.49),
=10.06-10.01,
=0.05;
(2)2000-1998+1996-1994+…-6+4-2,
=(2000-1998)+(1996-1994)+…+(8-6)+(4-2),
=2×500,
=1000;
(3)
×(0.875×12.4+1+4.4×
)×
-
,
=
×(
×12.4+1+4.4×
)-
,
=
×[(12.4+4.4)×
+1]-
,
=
×[16.8×
+1]-
,
=
×[14.7+1]-
,
=
×15.7-
,
=
×(15+
)-
,
=10+
-
,
=10
;
(4)[1-(
+
)×2
]÷
,
=[1-(
+
)×2
]÷
,
=[1-(
+
)×2
]÷
,
=[1-
×
]÷
,
=[1-
]×
,
=
×
,
=
.
=(9.63+0.43)-(7.52+2.49),
=10.06-10.01,
=0.05;
(2)2000-1998+1996-1994+…-6+4-2,
=(2000-1998)+(1996-1994)+…+(8-6)+(4-2),
=2×500,
=1000;
(3)
| 1 |
| 2 |
| 7 |
| 8 |
| 4 |
| 3 |
| 1 |
| 4 |
=
| 2 |
| 3 |
| 7 |
| 8 |
| 7 |
| 8 |
| 1 |
| 4 |
=
| 2 |
| 3 |
| 7 |
| 8 |
| 1 |
| 4 |
=
| 2 |
| 3 |
| 7 |
| 8 |
| 1 |
| 4 |
=
| 2 |
| 3 |
| 1 |
| 4 |
=
| 2 |
| 3 |
| 1 |
| 4 |
=
| 2 |
| 3 |
| 7 |
| 10 |
| 1 |
| 4 |
=10+
| 7 |
| 15 |
| 1 |
| 4 |
=10
| 13 |
| 60 |
(4)[1-(
| 1 | ||
12+
|
| 1 |
| 10 |
| 1 |
| 2 |
| 11 |
| 25 |
=[1-(
| 1 | ||
|
| 1 |
| 10 |
| 1 |
| 2 |
| 11 |
| 25 |
=[1-(
| 2 |
| 25 |
| 1 |
| 10 |
| 1 |
| 2 |
| 11 |
| 25 |
=[1-
| 9 |
| 50 |
| 5 |
| 2 |
| 11 |
| 25 |
=[1-
| 9 |
| 20 |
| 25 |
| 11 |
=
| 11 |
| 20 |
| 25 |
| 11 |
=
| 5 |
| 4 |
点评:此题考查了整数、小数、分数的四则混合运算,注意运算顺序,运用运算技巧,灵活简算.
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