19. (6分)计算:
(1)$-8-(-14)+(-29)-(+7)$;
(2)$3-(\frac {1}{3}-\frac {1}{6}-\frac {3}{4})×24$;
(3)$-1^{4}-(1+0.5)×\frac {1}{3}÷(-4)^{2}$.
(1)$-8-(-14)+(-29)-(+7)$;
(2)$3-(\frac {1}{3}-\frac {1}{6}-\frac {3}{4})×24$;
(3)$-1^{4}-(1+0.5)×\frac {1}{3}÷(-4)^{2}$.
答案:
(1)-30
(2)17
(3)$-\frac{33}{32}$
(1)-30
(2)17
(3)$-\frac{33}{32}$
20. (6分)在数轴上表示下列各数,并用“<”号把它们按照从小到大的顺序排列.
$|-4|,-2^{2},2\frac {2}{3},-2,-0.5$.
$|-4|,-2^{2},2\frac {2}{3},-2,-0.5$.
答案:
|-4| = 4,$-2^2=-4$.在数轴上表示各数如图:
则$-2^2<-2<-0.5<2\frac{2}{3}<|-4|$.
|-4| = 4,$-2^2=-4$.在数轴上表示各数如图:
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