To solve these calculations, we need to first find a common denominator for each fraction.

( \frac{7}{220} + \frac{17}{330} )
Common denominator: 660
( \frac{7 \times 3}{220 \times 3} + \frac{17 \times 2}{330 \times 2} )
( \frac{21}{660} + \frac{34}{660} )
( \frac{55}{660} )
Simplified: ( \frac{11}{132} )

( 0.88 - \frac{2}{15} )
( \frac{88}{100} - \frac{2}{15} )
Common denominator: 300
( \frac{88 \times 3}{100 \times 3} - \frac{2 \times 20}{15 \times 20} )
( \frac{264}{300} - \frac{40}{300} )
( \frac{224}{300} )
Simplified: ( \frac{56}{75} )

( \left(\frac{1}{6} + \frac{5}{18}\right) - \left(\frac{1}{18} + \frac{1}{24}\right) )
( \frac{1}{6} + \frac{5}{18} - \frac{1}{18} - \frac{1}{24})
Common denominator for the first set of fractions: 18
( \frac{3}{18} + \frac{5}{18} - \frac{1}{18} - \frac{1}{24})
( \frac{7}{18} - \frac{1}{18} - \frac{1}{24})
Common denominator: 72
( \frac{7 \times 4}{18 \times 4} - \frac{1 \times 4}{18 \times 4} - \frac{1 \times 3}{24 \times 3})
( \frac{28}{72} - \frac{4}{72} - \frac{3}{72})
( \frac{21}{72} )
Simplified: ( \frac{7}{24} )