Answer:
p + 111 = 210
p = 99 
Step-by-step explanation:
Break the question down into parts.
<u>Convert each part into algebraic form</u> (numbers or symbols).
210                                =>   210
is equal to                    =>   =
the total of p and 111    =>   p + 111
Put the equation together:
210 = p + 111
Usually, the variable is on the left side:
p + 111 = 210
<u>To solve the equation is to isolate "p"</u>. This means to keep "p" on the left, and move everything else to the right side. When moving something, do the <u>reverse operation</u> to both sides of the equation.
p + 111 = 210            "111" should be on the left. It's opposite is -111.
p + 111 - 111 = 210 - 111                Simplify. "111" cancels out on the left.
p = 99                      Solved for "p"