1. $-\dfrac{3}{2}$的相反数是(
A.$-\dfrac{2}{3}$
B.$\dfrac{2}{3}$
C.$-\dfrac{3}{2}$
D.$\dfrac{3}{2}$
D
)A.$-\dfrac{2}{3}$
B.$\dfrac{2}{3}$
C.$-\dfrac{3}{2}$
D.$\dfrac{3}{2}$
答案:
D
2. 太阳的半径约为696 000 km,数据696 000用科学记数法可表示为(
A.$0.696×10^{6}$
B.$6.96×10^{5}$
C.$6.96×10^{6}$
D.$0.696×10^{5}$
B
)A.$0.696×10^{6}$
B.$6.96×10^{5}$
C.$6.96×10^{6}$
D.$0.696×10^{5}$
答案:
B
3. 在有理数$-\dfrac{8}{3}$,0,$-3$,$|-2|$中,最小的数是(
A.$-\dfrac{8}{3}$
B.0
C.$-3$
D.$|-2|$
C
)A.$-\dfrac{8}{3}$
B.0
C.$-3$
D.$|-2|$
答案:
C
4. 下列各组式子中,相等的是(
A.$(-3)^{2}和-3^{2}$
B.$|-2|^{3}和|-2^{3}|$
C.$-(+2)和+|-2|$
D.$(-2)^{3}和-3^{2}$
B
)A.$(-3)^{2}和-3^{2}$
B.$|-2|^{3}和|-2^{3}|$
C.$-(+2)和+|-2|$
D.$(-2)^{3}和-3^{2}$
答案:
B
5. 计算$2\dfrac{1}{7}+(-2\dfrac{3}{4})+4\dfrac{6}{7}+(-7\dfrac{1}{4})$时,运算律用得正确且最恰当的是(
A.$[2\dfrac{1}{7}+(-7\dfrac{1}{4})]+[(-2\dfrac{3}{4})+4\dfrac{6}{7}]$
B.$(2\dfrac{1}{7}+4\dfrac{6}{7})+[(-2\dfrac{3}{4})+(-7\dfrac{1}{4})]$
C.$[(-2\dfrac{3}{4})+7\dfrac{1}{4}]+(2\dfrac{1}{7}+4\dfrac{6}{7})$
D.$(-7\dfrac{1}{4}+2\dfrac{3}{4})+(2\dfrac{1}{7}+4\dfrac{6}{7})$
B
)A.$[2\dfrac{1}{7}+(-7\dfrac{1}{4})]+[(-2\dfrac{3}{4})+4\dfrac{6}{7}]$
B.$(2\dfrac{1}{7}+4\dfrac{6}{7})+[(-2\dfrac{3}{4})+(-7\dfrac{1}{4})]$
C.$[(-2\dfrac{3}{4})+7\dfrac{1}{4}]+(2\dfrac{1}{7}+4\dfrac{6}{7})$
D.$(-7\dfrac{1}{4}+2\dfrac{3}{4})+(2\dfrac{1}{7}+4\dfrac{6}{7})$
答案:
B
6. 数轴上一动点A向左移动3个单位长度到达点B,再向右移动4个单位长度到达点C,若点C表示的数为1,则点A表示的数为(
A.7
B.1
C.0
D.$-1$
C
)A.7
B.1
C.0
D.$-1$
答案:
C
7. 若a是最小的自然数,b是最小的正整数,c是最大的负整数,则a,b,c三数之和为(
A.$-1$
B.0
C.1
D.2
B
)A.$-1$
B.0
C.1
D.2
答案:
B
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