Simplify the following expression: ((32)/(3) of 21 + 3(3)/(4) / (3)/(8) - 4(1)/(2) x 3(1)/(3)5(5)/(8) x 1(1)/(3) - (1)/(4) of 4(2)/(3) / (7)/(10))

Step 1: Convert all mixed numbers to improper fractions.
The given expression is:

$$\frac{3\frac{2}{3} \text{ of } 21 + 3\frac{3}{4} \div \frac{3}{8} - 4\frac{1}{2} \times 3\frac{1}{3}}{5\frac{5}{8} \times 1\frac{1}{3} - \frac{1}{4} \text{ of } 4\frac{2}{3} \div \frac{7}{10}}$$

Converting all mixed numbers to improper fractions:
$3\frac{2}{3} = \frac{3 \times 3 + 2}{3} = \frac{11}{3}$
$3\frac{3}{4} = \frac{3 \times 4 + 3}{4} = \frac{15}{4}$
$4\frac{1}{2} = \frac{4 \times 2 + 1}{2} = \frac{9}{2}$
$3\frac{1}{3} = \frac{3 \times 3 + 1}{3} = \frac{10}{3}$
$5\frac{5}{8} = \frac{5 \times 8 + 5}{8} = \frac{45}{8}$
$1\frac{1}{3} = \frac{1 \times 3 + 1}{3} = \frac{4}{3}$
$4\frac{2}{3} = \frac{4 \times 3 + 2}{3} = \frac{14}{3}$

Substitute these into the expression:

$$\frac{\frac{11}{3} \text{ of } 21 + \frac{15}{4} \div \frac{3}{8} - \frac{9}{2} \times \frac{10}{3}}{\frac{45}{8} \times \frac{4}{3} - \frac{1}{4} \text{ of } \frac{14}{3} \div \frac{7}{10}}$$

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