Students have been working on modelling three digit numbers in a variety of ways.
For example: 329 can be shown as 3 hundreds, 2 tens, and 9 ones, (300+20+9) or you can regroup and show it as 2 hundreds, 12 tens and 9 ones (200+120+9). There are several different possibilities and combinations.
Playing with numbers this way will help deepen our understanding of how and why we trade and regroup when adding and subtracting larger numbers. Here the students are practicing with the base ten blocks.