Are you sensing something?
Have you ever tried to guess how many jelly beans are in a jar? Or "guesstimated" the number of people who were at the concert last night? Number sense is your intuitive recognition of numbers and their relationships. You can tell, for instance, that one group of circles contains more shapes than another, even though you don't know the exact number. This is an ability shared with many animals, and helps them (and us, in days gone by) to survive.