At the park, Dimitri saw families riding bicycles and tricycles. Bicycles have two wheels and tricycles have three wheels.  6 adults were riding bicycles and 15 children were riding tricycles.   How many wheels did Dimitri see at the park?
At the park, Dimitri saw families riding bicycles and tricycles. Bicycles have [NUMBER] wheels and tricycles have [NUMBER] wheels. [NUMBER] adults were riding bicycles and [NUMBER] children were riding tricycles. How many wheels did Dimitri see at the park?
Dimitri saw 2 x 6 = <<2*6=12>>12 wheels on the bicycles.
He saw 15 x 3 = <<15*3=45>>45 wheels on the tricycles.
He saw a total of 12 + 45 = <<12+45=57>>57 wheels.
#### 57