This is a pre/post test used with the common core standard 1.NBT.5. This assessment focuses on mentally finding 10 more or 10 less than a given 2-digit number, without having to count; Explain the reasoning used. I use the assessment as a pre test at the beginning of a study. The recording sheet then helps me create small groups for guided math lessons based on who needs what. Then I use the same assessment at the end of the study to show student progress over the period. I run the assessment off front and back so I have the pre and post test for a child on the same sheet of paper.