Numerous activities can be done with 100 items. Ask students to bring 100 pictures cut out of magazines. Have them create a poster collage with the pictures. Another idea is to ask each student to create something out of 100 items and bring it to school. It can be a house made out of Legos or cookies, or students can create something out of small candies or other small objects. Making a trail mix is another idea. Assign an item for each student to bring. Ask each student to bring 100 pieces of the item. During the party have the students mix all of the items together to make a trail mix made up of all the different items brought, including miniature marshmallows, cereal pieces and small candies. The trail mix contains many different items, depending on the amount of children in the class. Each child then chooses and counts 100 items out of the mix.
Give each student a coin. Have them toss the coin 100 times and tally the results by heads and tails. Guess the jar is a game that works for elementary students, too. Several jars are filled with items like candy or small toys. The kids guess which jar has exactly 100 items in it. Another fun game using dice is a number chart. Give children a chart with boxes labeled one through 100. The kids group off and begin rolling a die. As a child rolls it, he colors in the corresponding amounts of squares on the chart. If he rolls a 5, he colors the first 5 boxes. If he rolls a 6 on the next roll, he colors in the next 6 squares. The game is finished when one child reaches 100.
A lot of classes incorporate physical activities into this fun day. Students -- and teachers -- complete 100 exercises consisting of 10 jumping jacks, 10 toe touches and 10 push-ups. Any combination of exercises is good. After 100 exercises are completed, the students take a 100-second silence break.
Bring a large cake to the classroom to celebrate the 100th day. Divide 100 pieces of candy between all the children and let each take a turn decorating the cake with his pieces of candy. The popcorn game is a fun game that kids love. The teacher brings in a hot air popcorn machine and 100 kernels of unpopped popcorn. The kernels are placed in the machine and turned on while the lid is off the popper allowing the popcorn to fly out of the machine.