When you have completed this page, try the Equations 5 Quiz.
RECAP: On the previous pages we learned about equations containing multiplication and numbers behind one mystery door. On this page we will explore equations with division and one mystery door.
Let's consider an example containing division with only positive numbers. One easy of representing a division problem is to write the dividend as the numerator of a fraction and the divisor as the denominator. Also remember that any whole number can be written as a fraction by
16


= 
4

The first step is to multiply both sides by the mystery door  strange as that sounds.

* 
16


= 

* 
4

By cross canceling the mystery doors on the left side, one has the following equation, Sixteen equals mystery door times four. Then you must divide both sides by four. This leaves you with sixteen divided by four which is four on one side and mystery door times one on the other side. Your final answer is four, the number behind the mystery door.
16/


= 

* 
4/

4 
= 

The same process is true with positive and negative numbers. Mystery door divided by negative three equals negative two. Both sides must be multiplied by negative three. The three on the left side of the equation cancels out the three that is in the denominator of the mystery door over negative three. On the right side, negative two times three equals negative six.

= 
2 


= 
2 * 3 

= 
6 
By looking back to the original equation we see that: