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1.计算-7.2-0.9-5.6+1.7的结果是
-12
。答案
1. -12.
2. 计算$(-50) × ( \frac{2}{5} - \frac{1}{10} ) ÷ ( -\frac{3}{2} )$的结果是
10
.答案
2. 10.
3. -2与-3和的平方除以-25等于
-1
.答案
3. -1.
4.算式$\frac{2}{5}×(-\frac{6}{7})÷(\frac{1}{2}-2)$用语言表述是
$\frac{2}{5}$与$-\frac{6}{7}$的积除以$\frac{1}{2}$与2的差
.答案
4. $\frac{2}{5}$与$-\frac{6}{7}$的积除以$\frac{1}{2}$与2的差.
5. 在横线上填上适当的式子,把下列运算过程补充完整:
$[ 3\dfrac{3}{4} ÷ \_\_\_\_\_\_ + 0.4 × (-\dfrac{5}{2})^2 ] ÷ (-\dfrac{5}{3})$
$= [ \dfrac{15}{4} × (-2) + \dfrac{2}{5} × \_\_\_\_\_\_ ] ÷ (-\dfrac{5}{3})$
$= [ \_\_\_\_\_\_ + \_\_\_\_\_\_ ] ÷ (-\dfrac{5}{3})$
$= ( \_\_\_\_\_\_ ) × ( \_\_\_\_\_\_ ) = 3.$
$[ 3\dfrac{3}{4} ÷ \_\_\_\_\_\_ + 0.4 × (-\dfrac{5}{2})^2 ] ÷ (-\dfrac{5}{3})$
$= [ \dfrac{15}{4} × (-2) + \dfrac{2}{5} × \_\_\_\_\_\_ ] ÷ (-\dfrac{5}{3})$
$= [ \_\_\_\_\_\_ + \_\_\_\_\_\_ ] ÷ (-\dfrac{5}{3})$
$= ( \_\_\_\_\_\_ ) × ( \_\_\_\_\_\_ ) = 3.$
答案
5. $(-\dfrac{1}{2})$或$(-0.5), \dfrac{25}{4}, -\dfrac{15}{2}, \dfrac{5}{2}, -5, -\dfrac{3}{5}.$
6. 计算 $10÷\frac{1}{7}×(-7)$，下列对式子变形正确的是 ……………………【 】
A.$10×7×7$
B.$10×7×(-7)$
C.$10×\frac{1}{7}×7$
D.$10÷[\frac{1}{7}×(-7)]$
A.$10×7×7$
B.$10×7×(-7)$
C.$10×\frac{1}{7}×7$
D.$10÷[\frac{1}{7}×(-7)]$
答案
6. B.
7.下列各式计算正确的是 ……【 】
A.$1×2 + (-2)×3 = 3$
B.$42÷6 - (-24)÷4 = 1$
C.$8÷(-4)×(-2) = 1$
D.$(1 - \frac{1}{2})^2 = (\frac{1}{2} - 1)^2$
A.$1×2 + (-2)×3 = 3$
B.$42÷6 - (-24)÷4 = 1$
C.$8÷(-4)×(-2) = 1$
D.$(1 - \frac{1}{2})^2 = (\frac{1}{2} - 1)^2$
答案
7. D.
8. 下列计算过程正确的是 ……【 】
A.$\frac{3}{4} ÷ 3 × \frac{4}{3} = \frac{3}{4} ÷ (3 × \frac{4}{3})$
$= \frac{3}{4} ÷ 4 = \frac{3}{16}$
B.$(-144) ÷ [(-3)^2 - (-4)^2]$
$= (-144) ÷ 9 - (-144) ÷ 16 = -7$
C.$-35 × [\frac{1}{7} - (-1\frac{3}{5})]$
$= -35 × \frac{1}{7} - 35 × \frac{8}{5} = -61$
D.$1\frac{1}{2} - \frac{1}{3} + \frac{5}{6} - 1\frac{1}{4}$
$= (\frac{5}{6} - \frac{1}{3}) - (1\frac{1}{2} - 1\frac{1}{4})$
$= \frac{1}{2} - \frac{1}{4} = \frac{1}{4}$
A.$\frac{3}{4} ÷ 3 × \frac{4}{3} = \frac{3}{4} ÷ (3 × \frac{4}{3})$
$= \frac{3}{4} ÷ 4 = \frac{3}{16}$
B.$(-144) ÷ [(-3)^2 - (-4)^2]$
$= (-144) ÷ 9 - (-144) ÷ 16 = -7$
C.$-35 × [\frac{1}{7} - (-1\frac{3}{5})]$
$= -35 × \frac{1}{7} - 35 × \frac{8}{5} = -61$
D.$1\frac{1}{2} - \frac{1}{3} + \frac{5}{6} - 1\frac{1}{4}$
$= (\frac{5}{6} - \frac{1}{3}) - (1\frac{1}{2} - 1\frac{1}{4})$
$= \frac{1}{2} - \frac{1}{4} = \frac{1}{4}$
答案
8. C.
9. $\frac{1}{2} × (-14) ÷ (-7)$
10. $1 - 3 × \frac{1}{3} ÷ (-2)$
11. $-1 ÷ 3 × \frac{1}{3}$
12. $1 + 2^2 × (-\frac{1}{5})$
13. $2 - 6 ÷ (-3) × (-\frac{1}{2})$
14. $(-\frac{1}{2} + \frac{2}{3} - \frac{1}{4}) × |-24|$
15. $3\frac{1}{2} - (-1\frac{1}{2})^2 ÷ 2$
16. $2 × \frac{1}{19} × \frac{2}{3} - \frac{7}{19}$
17. $-1^2 - 4 ÷ (-3) ÷ (-\frac{1}{3})$
18. $[5\frac{1}{2} - (1\frac{1}{4} ÷ 1\frac{2}{3} + 3\frac{1}{2})] ÷ (-1\frac{1}{8})$
19. $-1^4 × 4 - (1 - 0.5) × \frac{2}{7} × [2 - (-3)^2]$
20. $[50 - (\frac{7}{9} - \frac{11}{12} + \frac{1}{6}) × (-6)^2] ÷ (-\frac{1}{2})^3 ÷ (-7)^2$
10. $1 - 3 × \frac{1}{3} ÷ (-2)$
11. $-1 ÷ 3 × \frac{1}{3}$
12. $1 + 2^2 × (-\frac{1}{5})$
13. $2 - 6 ÷ (-3) × (-\frac{1}{2})$
14. $(-\frac{1}{2} + \frac{2}{3} - \frac{1}{4}) × |-24|$
15. $3\frac{1}{2} - (-1\frac{1}{2})^2 ÷ 2$
16. $2 × \frac{1}{19} × \frac{2}{3} - \frac{7}{19}$
17. $-1^2 - 4 ÷ (-3) ÷ (-\frac{1}{3})$
18. $[5\frac{1}{2} - (1\frac{1}{4} ÷ 1\frac{2}{3} + 3\frac{1}{2})] ÷ (-1\frac{1}{8})$
19. $-1^4 × 4 - (1 - 0.5) × \frac{2}{7} × [2 - (-3)^2]$
20. $[50 - (\frac{7}{9} - \frac{11}{12} + \frac{1}{6}) × (-6)^2] ÷ (-\frac{1}{2})^3 ÷ (-7)^2$
答案
9. 1.
10. $\frac{3}{2}.$
11. $-\frac{1}{9}.$
12. $\frac{1}{5}.$
13. 1.
14. $-2.$
15. $\frac{19}{8}.$
16. $-\frac{17}{57}.$
17. $-5.$
18. $-\frac{10}{9}.$
19. $-3.$
20. $-8.$
10. $\frac{3}{2}.$
11. $-\frac{1}{9}.$
12. $\frac{1}{5}.$
13. 1.
14. $-2.$
15. $\frac{19}{8}.$
16. $-\frac{17}{57}.$
17. $-5.$
18. $-\frac{10}{9}.$
19. $-3.$
20. $-8.$
