计算(写出计算过程).(1)(-3.14)+(+4.96)+(+2.14)+(-7.96)(2)(−218)+(+5)+

计算(写出计算过程).
(1)(-3.14)+(+4.96)+(+2.14)+(-7.96)
(2)(−2
1
8
)+(+5)+(−3
1
2
)+(+1.125)+(+4
1
2
)

(3)(-3.2)×1.5
(4)1
3
4
×(−8)

(5)(−4)×
1
3
×(−25)×(−6)

(6)24×(
1
8
1
6
1
4
)

(7)([1/4−
1
9
1
18
1
12])×(-36)
(8)-99[98/99
×
varigo 1年前 已收到1个回答 举报

tonglw 幼苗

共回答了17个问题采纳率:94.1% 举报

解题思路:(1)(2)先化简,再分类计算;
(3)(4)(5)先判定符号,再按照乘法法则计算;
(6)(7)(8)利用乘法分律率简算;
(9)0乘任何数都为0;
(10)先算除法,再算减法;
(11)先算乘方,再算乘法,最后算减法;
(12)先算乘方,再算乘除,最后算加减.

(1)(-3.14)+(+4.96)+(+2.14)+(-7.96)
=-3.14+2.14+4.96-7.96
=-1-3
=-4;

(2)(−2
1
8)+(+5)+(−3
1
2)+(+1.125)+(+4
1
2)
=-2.125+1.125-3.5+4.5+5
=-1+1+5
=5;

(3)(-3.2)×1.5
=-4.8;

(4)1
3
4×(−8)
=-22;

(5)(−4)×
1
3×(−25)×(−6)
=-4×[1/3]×25×6
=-200;

(6)24×(
1
8−
1
6−
1
4)
=24×[1/8]-24×[1/6]-24×[1/4]
=3-4-6
=-7;

(7)([1/4−
1
9−
1
18−
1
12])×(-36)
=[1/4]×(-36)-[1/9]×(-36)-[1/18]×(-36)-[1/12]×(-36)
=-9+4+2+3
=0;

(8)-99[98/99×9
=(-100+
1
99])×9
=-100×9+[1/99]×9
=-900+[1/11]
=-899[10/11];

(9)2011×2
1
3×0×(−389)
=0;

(10)-125÷(-25)-64÷(-4)
=5+16
=21;

(11)2×(-3)2−5÷
1
2×2
=2×9-5×2×2
=18-20
=-2;

(12)(−2)3×8−8×(
1
2)3+8÷
1
8
=-8×8-8×[1/8]+8×8
=-64-1+64
=-1.

点评:
本题考点: 有理数的混合运算.

考点点评: 此题考查有理数的混合运算,注意运算顺序,灵活运用运算定律使计算简便.

1年前

5
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