This power point presentation was designed to introduce the concept of ungrouping a ten into 10 ones within a 2-digit number. This skill is essential when learning 2-digit subtraction. I made this presentation for 2nd grade, but it may be a good review for 3rd graders. It includes guided practice with ungrouping, explainations of value and "math talk", and an ungrouping T-chart. The tens and ones are animated to help students understand the trade that occurs. Students would benefit from having base ten blocks and a marker board (or paper) to follow along with the presentation.