Simplify each expression.

1. $- \frac { 4 } { 5 } + \frac { 7 } { 12 }$ 

   Hint (a):

   Find a common denominator and simplify.

   More Help (a):

   $\left(-\frac{4}{5}\right)\left(\frac{12}{12}\right) + \left(\frac{7}{12}\right)\left(\frac{5}{5}\right)$

   Answer (a):

   $-\frac{13}{60}$

2. $\frac { 5 } { 9 } + ( - \frac { 1 } { 4 } )$ 

   Hint (b):

   Remember that adding a negative number is essentially subtraction.

   Answer (b):

   $\frac{11}{36}$

3. $- \frac { 3 } { 7 } \cdot \frac { 11 } { 12 }$ 

   Hint (c):

   Multiply the numerators together and the denominators together.

4. $- 1 \frac { 2 } { 3 } \cdot \frac { 4 } { 5 }$ 

   Hint (d):

   Turning the first fraction into an fraction greater than one may prove to be more helpful.