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计算(1)22+(-5)-(-2)+8(2)1213×(-20)+113×(-20)(3)(16-27+23)÷(-142)(4)(-21.6)+3-7.4+(-0.4)

题目详情
计算
(1)22+(-5)-(-2)+8      
(2)
12
13
×(-20)+
1
13
×(-20)
(3)(
1
6
-
2
7
+
2
3
)÷(-
1
42
)       
(4)(-21.6)+3-7.4+(-0.4)
▼优质解答
答案和解析
(1)22+(-5)-(-2)+8
=(22+2+8)-5
=27;     
(2)
12
13
×(-20)+
1
13
×(-20)
=-20×(
12
13
+
1
13

=-20;
(3)(
1
6
-
2
7
+
2
3
)÷(-
1
42

=-
1
6
×42+
2
7
×42-
2
3
×42
=-7+12-28
=-23;       
(4)(-21.6)+3-7.4+(-0.4)
=-(21.6+0.4+7.4)+3
=-29.4+3
=-26.4.