计算下列各题(1)(-2.4)+(-3.7)+(+4.2)+0.7+(-4.2);(2)13+(-34)+(-13)+(-14)+1819.-数学

题目简介

计算下列各题(1)(-2.4)+(-3.7)+(+4.2)+0.7+(-4.2);(2)13+(-34)+(-13)+(-14)+1819.-数学

题目详情

计算下列各题
(1)(-2.4)+(-3.7)+(+4.2)+0.7+(-4.2);
(2)
1
3
+(-
3
4
)+(-
1
3
)+(-
1
4
)+
18
19
题型:解答题难度:中档来源:不详

答案

(1)(-2.4)+(-3.7)+(+4.2)+0.7+(-4.2)
=[(-2.4)+(-3.7)+(-4.2)]+[(+4.2)+0.7]
=-10.3+4.9
=-5.4;

(2)class="stub"1
3
+(-class="stub"3
4
)+(-class="stub"1
3
)+(-class="stub"1
4
)+class="stub"18
19

=[class="stub"1
3
+(-class="stub"1
3
)]+[(-class="stub"3
4
)+(-class="stub"1
4
)+class="stub"18
19

=-1+class="stub"18
19

=-class="stub"1
19

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