Evaluate the expression.
You have a piece of wood that is 23 3/8 feet long.
You need to cut pieces that are 1 3/8 feet long. 
How many pieces can you cut?

Divide

(23 3/8) ÷ (1 3/8)

I assume you know how to change mixed numbers and
fractions into improper fractions, and vice-versa.
If not, post again asking how to.

Change them to improper fractions:

(187/8)÷ (11/8)

Invert the second fraction and change the ÷ to ×
  
(187/8)×(8/11)

Cancel the 8's

        1
187/8)×(8/11)
    1    

Cancel the ll into the 187. It goes 17 times

 17     1
187/8)×(8/11)
    1      1

So the answer is 17 pieces.

Edwin