Simplify each expression.

1. $- \frac { 11 } { 15 } + \frac { 3 } { 4 }$

   Hint (a):

   Find a common denominator.

   Help (a):

   $- \frac{44}{60} + \frac{45}{60}$

   Answer (a):

   $\frac{1}{60}$

2. $5 \frac { 2 } { 9 } + ( - 2 \frac { 1 } { 10 } )$

   Hint (b):

   Use the associative property of addition.

   Help (b):

   $(5-2) + ( \frac{2}{9} - \frac{1}{10} )$

   Answer (b):

   $3 \frac{11}{90}$

3. $- \frac { 7 } { 8 } + \frac { 2 } { 3 } - ( - \frac { 1 } { 4 } )$

   Hint (c):

   See part (a).