The "number of pips on a double domino set" problem is introduced and a solution is provided to the double 9 set problem. The aim of Solve It! is to provide teachers with meaningful, mathematically rich problems that invoke thoughtful and innovative student responses. Solve It! poses a problem for classroom use and gives a solution to a previously published problem. Solve It! is a regular department of Teaching Children Mathematics. Student solutions are highlighted in The Thinking of Students department of Mathematics Teaching in the Middle School.