This activity is for younger elementary for the 100th day of school. The students are given jars with school supplies in them of different sizes to guess or estimate the amount in each jar. I divided the class into 5 groups. Each group was given a jar and each student received their own response sheet. I gave the students about 2-3 minutes with each jar to write down their estimations. The students then rotated the jars clockwise. Once all the groups had a chance to guess, they worked as a group to count how many were in the jars. I suggested using their grouping methods to make it go faster. Each group then shared their jar's amount with the class and we compared answers. I found small jars for $1 a piece that I still use for storage!