Place value activities will become very important once first graders begin to work with larger (i.e, 2-digit) numbers. Here are a few to get you started:
Kids love to do math with money. If you have a bunch of coins, take out the pennies and let kids count them. Ask kids to put pennies in stacks of 10 and count them by 10s when they are done. Was it harder or easier to count them this way? What might happen if you tried to count all the pennies one at a time?
Players will need a bunch of dried beans. Take a handful of dried beans and guess how many there are. Then count the beans: count up to ten, then put those in a pile; count out 10 more beans and do the same thing, until you don't have enough to make another tens pile. Count by counting piles by 10, then adding on the ones that were left over.
Place value activities that use dice give kids the impression they are playing a game. For this activity, give children place value manipulatives such as straws, that can be bundled into groups of 10 with rubber bands, or Base 10 blocks. It is also helpful to use a place value chart to keep track of tens and ones.
To play, two children each roll a die. Then they put them together and decide which number to make. For example, if one child rolls a 1 and the other rolls a 4, they can make either 14 or 41. When they say "go", each one tries to be fastest to build that number. (They will both make the same number.) When they are done, they compare what they built to check their work.
This game is very like "Roll It, Build It", but with a small twist. Children are given place value manipulatives, a place value chart and two dice. Before playing a round, kids decide who will be Big and who will be Small (Small gets to roll the dice; kids should trade off roles). Each child rolls one die. Small uses the dice to make the smaller number; Big uses the dice to make the bigger number. Each child writes down their number and then makes it, using the manipulatives. When they are done, children compare their numbers. (This is an eye-opening game for kids, since it shows very concretely the difference position makes in determining how big or small a number is.) Play again, switching roles.
Some place value activities need no materials at all--just a great idea, some enthusiasm, and maybe a funky hat. Check out this great video showing how one teacher helps his class understand place value. It's hilarious!
Make up regrouping stories. Tell the kids a story, and have them use place value manipulatives (such as counters and a place value chart or a tens frame) to solve the story problems. For example, "You got 26 pieces of candy going trick or treat on Halloween. Then you got another 36 pieces of candy at your friend's Halloween party! How many candies did you get altogether?" (A problem like this would be fun to solve with actual candy... just an idea!)
Write an addition or subtraction problem on the board for kids to solve with manipulatives. To mix it up and make problem solving more exciting, have different types of manipulatives at each table. You might have beans and cups on one, pipe cleaners and rubber bands at another, Base 10 at another, tens frames on yet another, and so on. After each problem, have groups get up and move to the table next to theirs. By the end of 6 or 7 questions, the kids will have rotated through all the tables, gotten some good practice with regrouping, and will have had a great time!
A final word: Don't feel discouraged if first graders do not seem to "get" place value in first grade. The main focus right now is on exposure; they need to play with place value concepts over and over again. Spend plenty of time doing place value activities and place value games, and it will eventually begin to make sense.