Word Problem

Kyle is keeping track of the amount of snowfall at the ski resort this month.  So far it has snowed three times.  The first snowfall was 12 centimetres.  Last week there was a snowstorm that dumped 55 centimetres.  The most recent snowfall was 31 centimetres. 

Write the math equation: ______________________

How many centimetres of snowfall has the resort
seen so far this month? ______

Show your work!