Grouping by 5s to 100 challenge

This can be done by a young child, even if they don't yet know the number sequence to count to 100.
If using cheerios, a half cup will be more than enough.
We make a "4 square" and add one in the middle to make a "5 star" - young children can do this without counting (this important math skill of visualizing quantities is called 'subitizing')
Two '5s' make 10 (put them side by side)
Continue making sets of two 5s (aka 10) until you have 10 sets of 10
We do this to celebrate our school's birthday (102!), but this is also a fun activity for hundredth day of school math activity.