计算 $(1)3 \dfrac {1}{2}+(- \dfrac {1}{2})-(- \dfrac {1}{3})+2 \dfrac {2}{3}(2)-8^{2}+3×(-2)^{2}+(-6)÷(- \dfrac {1}{3})^{2}(3)4 \dfrac {1}{2}×[-9×(- \dfrac {1}{3})^{2}-0.8]÷(-5 \dfrac {1}{4})$； $(4)( \dfrac {5}{12}+ \dfrac {2}{3}- \dfrac {3}{4})×(-12)(5)-2^{4}-[(-3)^{2}-(1-2^{3}× \dfrac {5}{4})÷(-2)](6)(-96)×(-0.125)+96× \dfrac {1}{8}+(-96)× \dfrac {5}{4}(7)(3a-2)-3(a-5)(8)(4a^{2}b-5ab^{2})-(3a^{2}b-4ab^{2})(9)x-2[y+2x-(3x-y)](10) \dfrac {1}{2}m-2(m- \dfrac {1}{3}n^{2})-( \dfrac {3}{2}m- \dfrac {1}{3}n^{2}).$

1. 去括号并对加减项重组

$3 \dfrac{1}{2} + \left(-\dfrac{1}{2}\right) - \left(-\dfrac{1}{3}\right) + 2 \dfrac{2}{3} = 3 \dfrac{1}{2} - \dfrac{1}{2} + \dfrac{1}{3} + 2 \dfrac{2}{3}$

2. 分组计算得出最终结果

$= \left(3 \dfrac{1}{2} - \dfrac{1}{2}\right) + \left(\dfrac{1}{3} + 2 \dfrac{2}{3}\right) = 3 + 3 = 6$

1. 计算乘方部分

$-8^2 = -64, \quad (-2)^2 = 4, \quad \left(-\dfrac{1}{3}\right)^2 = \dfrac{1}{9}$

2. 计算乘除法与加减法

$-64 + 3 \times 4 + (-6) \div \dfrac{1}{9} = -64 + 12 - 54 = -106$

1. 计算括号内部的表达式

$-9 \times \left(-\dfrac{1}{3}\right)^2 - 0.8 = -9 \times \dfrac{1}{9} - 0.8 = -1 - 0.8 = -1.8 = -\dfrac{9}{5}$

2. 化带分数为假分数并进行乘除计算

$4 \dfrac{1}{2} = \dfrac{9}{2}, \quad -5 \dfrac{1}{4} = -\dfrac{21}{4}$
$\dfrac{9}{2} \times \left(-\dfrac{9}{5}\right) \div \left(-\dfrac{21}{4}\right) = \dfrac{9}{2} \times \left(-\dfrac{9}{5}\right) \times \left(-\dfrac{4}{21}\right) = \dfrac{54}{35} = 1 \dfrac{19}{35}$

1. 展开乘法分配律

$\left(\dfrac{5}{12} + \dfrac{2}{3} - \dfrac{3}{4}\right) \times (-12) = \dfrac{5}{12} \times (-12) + \dfrac{2}{3} \times (-12) - \dfrac{3}{4} \times (-12)$

2. 约分计算得出结果

$= -5 - 8 + 9 = -4$

1. 计算小括号内的乘方与乘减法

$1 - 2^3 \times \dfrac{5}{4} = 1 - 8 \times \dfrac{5}{4} = 1 - 10 = -9$

2. 计算中括号内的表达式

$[(-3)^2 - (-9) \div (-2)] = [9 - 4.5] = 4.5$

3. 计算最终结果

$-2^4 - 4.5 = -16 - 4.5 = -20.5$

1. 化小数为分数并转化符号

$-0.125 = -\dfrac{1}{8}$
$(-96) \times (-0.125) + 96 \times \dfrac{1}{8} + (-96) \times \dfrac{5}{4} = 96 \times \dfrac{1}{8} + 96 \times \dfrac{1}{8} - 96 \times \dfrac{5}{4}$

2. 提取公因数 96 快速求值

$= 96 \times \left(\dfrac{1}{8} + \dfrac{1}{8} - \dfrac{5}{4}\right) = 96 \times \left(\dfrac{1}{4} - \dfrac{5}{4}\right) = 96 \times (-1) = -96$

1. 去括号

$(3a-2) - 3(a-5) = 3a - 2 - 3a + 15$

2. 合并同类项

$= (3a - 3a) + (-2 + 15) = 13$

1. 去括号

$(4a^2b - 5ab^2) - (3a^2b - 4ab^2) = 4a^2b - 5ab^2 - 3a^2b + 4ab^2$

2. 合并同类项

$= (4a^2b - 3a^2b) + (-5ab^2 + 4ab^2) = a^2b - ab^2$

1. 去除最内层小括号并化简中括号内表达式

$x - 2[y + 2x - (3x - y)] = x - 2[y + 2x - 3x + y] = x - 2[2y - x]$

2. 去除中括号并合并最终同类项

$= x - 4y + 2x = 3x - 4y$

1. 展开各项括号

$\dfrac{1}{2}m - 2\left(m - \dfrac{1}{3}n^2\right) - \left(\dfrac{3}{2}m - \dfrac{1}{3}n^2\right) = \dfrac{1}{2}m - 2m + \dfrac{2}{3}n^2 - \dfrac{3}{2}m + \dfrac{1}{3}n^2$

2. 按同类项分组合并计算

$= \left(\dfrac{1}{2}m - \dfrac{3}{2}m - 2m\right) + \left(\dfrac{2}{3}n^2 + \dfrac{1}{3}n^2\right) = (-m - 2m) + n^2 = -3m + n^2$