These are some activities I do to help my students build a strong understanding of place value.
On the first day, before my students come in, I break apart unifix cubes into a tub. Depending on the group size, I put in 80-120 cubes.
I have my students work together to count them. (Some groups will immediately start grouping them by color… others will just try and count them one by one… we discuss different strategies as they go. Once we have a group that groups them by colors, and then by tens, I make a big deal about that strategy and the other groups give it a try.)
With this activity, they figure out that you can be much more efficient by grouping objects into tens to count how many. That's the first step!
The next day, I give my kids bags (and boxes) of assorted items to count… I basically raid my manipulatives shelves and just pass them out. We do the same kind of thing as the day before—they group the items into tens to find out how many. The difference is that they will not end up with exact groups (and they do it independently). This allows for more conversations about tens and ones. (Again, be sure to stop and discuss strategies as you go… start with the most basic and work your way to the more complex.)
They take the items, group them in to sets of ten and count them.
Then we move to a more pictorial version. I have laminated cards that have an assortment of stickers on them. I have my students use a whiteboard marker to circle groups of ten. They find the total (how many groups of ten, how many ones, how many in all), come and tell me, and trade for a new card. It makes a great center after you’ve done it whole group!
Whenever introducing a math concept, remember that you must move from concrete to pictorial to abstract. Kids need to touch and feel to understand.