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1. 用科学记数法表示数 52 045 000=
5.204 5×10⁷
.答案
5.204 5×10⁷
2. 计算:
(1) $100÷(-2)^2 - (-2\dfrac{1}{2})÷(-\dfrac{2}{5})$;
(2) $-(\dfrac{1}{4}-\dfrac{1}{2})+9×(\dfrac{1}{6}-\dfrac{3}{8})$;
(3) $-1^{88} + 4×(-4)^3 + |-6|÷(-2)$;
(4) $100÷(-2)^2 - (-27)×(-\dfrac{1}{3})^2 + (-2)^3$.
(1) $100÷(-2)^2 - (-2\dfrac{1}{2})÷(-\dfrac{2}{5})$;
(2) $-(\dfrac{1}{4}-\dfrac{1}{2})+9×(\dfrac{1}{6}-\dfrac{3}{8})$;
(3) $-1^{88} + 4×(-4)^3 + |-6|÷(-2)$;
(4) $100÷(-2)^2 - (-27)×(-\dfrac{1}{3})^2 + (-2)^3$.
答案
(1) $\dfrac{75}{4}$
(2) $-\dfrac{13}{8}$
(3) $-260$
(4) $20$
(2) $-\dfrac{13}{8}$
(3) $-260$
(4) $20$
3. 计算:
(1)$(-1)-(-5\dfrac{1}{2})×\dfrac{4}{11}+(-8)÷[(-3)+5]$；
(2)$\dfrac{1}{5^3}×0.75-(-\dfrac{1}{5})^3×0.25+(\dfrac{1}{5})^3÷\dfrac{1}{4}$；
(3)$-2^3-[(-3)^2-2^2×\dfrac{1}{4}-8.5]÷(-\dfrac{1}{2})^2$。
(1)$(-1)-(-5\dfrac{1}{2})×\dfrac{4}{11}+(-8)÷[(-3)+5]$；
(2)$\dfrac{1}{5^3}×0.75-(-\dfrac{1}{5})^3×0.25+(\dfrac{1}{5})^3÷\dfrac{1}{4}$；
(3)$-2^3-[(-3)^2-2^2×\dfrac{1}{4}-8.5]÷(-\dfrac{1}{2})^2$。
答案
(1) $-3$
(2) $\dfrac{1}{25}$
(3) $-6$
(2) $\dfrac{1}{25}$
(3) $-6$
