10. 计算$6÷(-\dfrac{1}{2}+\dfrac{1}{3})$时,李明同学的计算过程如下:
原式$=6÷(-\dfrac{1}{2})+6÷\dfrac{1}{3}=-12+18=6$.
请你判断李明的计算过程是否正确. 若不正确, 请你写出正确的计算过程. 另用正确方法计算$(\dfrac{1}{2}-\dfrac{1}{6}+\dfrac{1}{9})÷(-\dfrac{1}{36})+36÷(\dfrac{1}{2}-\dfrac{1}{6}+\dfrac{1}{9})$的值.
原式$=6÷(-\dfrac{1}{2})+6÷\dfrac{1}{3}=-12+18=6$.
请你判断李明的计算过程是否正确. 若不正确, 请你写出正确的计算过程. 另用正确方法计算$(\dfrac{1}{2}-\dfrac{1}{6}+\dfrac{1}{9})÷(-\dfrac{1}{36})+36÷(\dfrac{1}{2}-\dfrac{1}{6}+\dfrac{1}{9})$的值.
答案
10. 不正确. 原式$=6÷(-\frac{1}{6})=6×(-6)=-36$. 最终结果为65.
11. 混合运算:
(1) $(-81)×4÷9÷(-16)$;
(2) $25÷5×(-\dfrac{1}{5})÷(-\dfrac{3}{4})$;
(3) $-9×(-11)÷3÷(-\dfrac{1}{3})$;
(4) $(-35)÷(-5)×\dfrac{1}{7}$;
(5) $(-\dfrac{3}{4})÷(-6)÷(-\dfrac{9}{4})$;
(6) $3×(-\dfrac{5}{6})÷(-1\dfrac{3}{4})$;
(7) $-\dfrac{7}{4}×(-\dfrac{1}{5})÷(-\dfrac{7}{5})$;
(8) $(-3\dfrac{1}{3})÷(-1\dfrac{2}{3})×(-\dfrac{2}{5})$;
(9) $\dfrac{7}{8}×(-\dfrac{3}{14})÷(-\dfrac{3}{8})$;
(10) $-3.5×(\dfrac{1}{6}-0.5)×\dfrac{3}{7}÷\dfrac{1}{2}$;
(11) $-1\dfrac{1}{2}÷(-\dfrac{1}{2}+\dfrac{1}{4})$;
(12) $(-60)÷(+3\dfrac{3}{5})$;
(13) $(-30\dfrac{3}{4})÷(-15)$;
(14) $(-0.33)÷(+\dfrac{1}{3})÷(-9)$;
(15) $(-2\dfrac{1}{2})÷(-5)×(-3\dfrac{1}{3})$;
(16) $(-81)÷2\dfrac{1}{4}×\dfrac{4}{9}÷(-16)$。
(1) $(-81)×4÷9÷(-16)$;
(2) $25÷5×(-\dfrac{1}{5})÷(-\dfrac{3}{4})$;
(3) $-9×(-11)÷3÷(-\dfrac{1}{3})$;
(4) $(-35)÷(-5)×\dfrac{1}{7}$;
(5) $(-\dfrac{3}{4})÷(-6)÷(-\dfrac{9}{4})$;
(6) $3×(-\dfrac{5}{6})÷(-1\dfrac{3}{4})$;
(7) $-\dfrac{7}{4}×(-\dfrac{1}{5})÷(-\dfrac{7}{5})$;
(8) $(-3\dfrac{1}{3})÷(-1\dfrac{2}{3})×(-\dfrac{2}{5})$;
(9) $\dfrac{7}{8}×(-\dfrac{3}{14})÷(-\dfrac{3}{8})$;
(10) $-3.5×(\dfrac{1}{6}-0.5)×\dfrac{3}{7}÷\dfrac{1}{2}$;
(11) $-1\dfrac{1}{2}÷(-\dfrac{1}{2}+\dfrac{1}{4})$;
(12) $(-60)÷(+3\dfrac{3}{5})$;
(13) $(-30\dfrac{3}{4})÷(-15)$;
(14) $(-0.33)÷(+\dfrac{1}{3})÷(-9)$;
(15) $(-2\dfrac{1}{2})÷(-5)×(-3\dfrac{1}{3})$;
(16) $(-81)÷2\dfrac{1}{4}×\dfrac{4}{9}÷(-16)$。
答案
11. (1)$\frac{9}{4}$ (2)$\frac{4}{3}$ (3)-99 (4)1 (5)$-\frac{1}{18}$
(6)$\frac{10}{7}$ (7)$-\frac{1}{4}$ (8)$-\frac{4}{5}$ (9)$\frac{1}{2}$ (10)1
(11)6 (12)$-16\frac{2}{3}$ (13)$\frac{41}{20}$ (14)0.11
(15)$-\frac{5}{3}$ (16)1
(6)$\frac{10}{7}$ (7)$-\frac{1}{4}$ (8)$-\frac{4}{5}$ (9)$\frac{1}{2}$ (10)1
(11)6 (12)$-16\frac{2}{3}$ (13)$\frac{41}{20}$ (14)0.11
(15)$-\frac{5}{3}$ (16)1
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