Assessment 

Formative Assessments are done throughout a unit or lesson. This allows a teacher to either continue with the lesson or adjust the lesson according to her assessment.

Summative assessments take place at the end of a unit.  Summative assessments allow a teacher to collect data to help see what students understand and may need further help with. 

Given before the start of a lesson or unit to see what a student already knows. Can help the teacher adjust the lesson according to the pre-assessment rsults.

A post-assessment is given at the end of a unit or lesson to see what knowledge the student has gained an understanding of. Can help the teacher keep track of a student's learning progress.