(1)12+(-23)+45+(-12)+(-13);(2)314-(-15)-(-318)+(-15);(3)(-81)÷214×49÷(-16);(4)23×(-5)-(-3)÷3128;(5)1

题目简介

(1)12+(-23)+45+(-12)+(-13);(2)314-(-15)-(-318)+(-15);(3)(-81)÷214×49÷(-16);(4)23×(-5)-(-3)÷3128;(5)1

题目详情

(1)
1
2
+(-
2
3
)+
4
5
+(-
1
2
)+(-
1
3
)
; 
(2)3
1
4
-(-15)-(-3
1
8
)+(-15)

(3)(-81)÷2
1
4
×
4
9
÷(-16)

(4)23×(-5)-(-3)÷
3
128

(5)19×
2
5
-0.4×(-18)+
2
5
×(-19)

(6)
1
18
÷(
2
3
+
1
6
-
1
2
)

(7)(-36
9
11
)÷9

(8)(
1
50
-1)×(
1
49
-1)×(
1
48
-1)×…×(
1
4
-1)×(
1
3
-1)×(
1
2
-1)
题型:解答题难度:中档来源:不详

答案

(1)class="stub"1
2
+(-class="stub"2
3
)+class="stub"4
5
+(-class="stub"1
2
)+(-class="stub"1
3
)

=[class="stub"1
2
+(-class="stub"1
2
)]+[(-class="stub"2
3
)+(-class="stub"1
3
)]+class="stub"4
5

=0-1+class="stub"4
5

=-class="stub"1
5
; 

(2)3class="stub"1
4
-(-15)-(-3class="stub"1
8
)+(-15)

=3class="stub"1
4
+15+3class="stub"1
8
-15
=6class="stub"3
8


(3)(-81)÷2class="stub"1
4
×class="stub"4
9
÷(-16)

=(-81)×class="stub"4
9
×class="stub"4
9
×(-class="stub"1
16

=1;

(4)23×(-5)-(-3)÷class="stub"3
128

=-115-(-3)×class="stub"128
3

=-115+128
=13;

(5)19×class="stub"2
5
-0.4×(-18)+class="stub"2
5
×(-19)

=19×class="stub"2
5
-class="stub"2
5
×(-18)+class="stub"2
5
×(-19)
=class="stub"2
5
(19+18-19)
=class="stub"2
5
×18
=class="stub"36
5


(6)class="stub"1
18
÷(class="stub"2
3
+class="stub"1
6
-class="stub"1
2
)

=class="stub"1
18
×class="stub"3
2
+class="stub"1
18
×6-class="stub"1
18
×2
=class="stub"1
12
+class="stub"1
3
-class="stub"1
9

=class="stub"3
36
+class="stub"12
36
-class="stub"4
36

=class="stub"11
36


(7)(-36class="stub"9
11
)÷9

=(-class="stub"405
11
)×class="stub"1
9

=-class="stub"45
11


(8)(class="stub"1
50
-1)×(class="stub"1
49
-1)×(class="stub"1
48
-1)×…×(class="stub"1
4
-1)×(class="stub"1
3
-1)×(class="stub"1
2
-1)

=(-class="stub"49
50
)×(-class="stub"48
49
)(-class="stub"47
48
)×…×(-class="stub"3
4
)(-class="stub"2
3
)(-class="stub"1
2

=class="stub"1
50

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