Quick Differentiated Math Fact Assessment

Right now we are in the midst of the state assessments, yet as I was helping my Kindergarten son get checked into his classroom I was reminded that the assessments teachers do to inform instruction can be quick and easily differentiated.  His teacher decided to put a math fact on their name tag so that each morning she could ask them that math fact, but I also noticed how varied the facts were (from 5+1 to 10 + 17).  What a quick way to differentiate and assess their math facts.