This free math video shows my 6 and 8-year-old daughters figuring out the squares of numbers 10 through 20. We use a variety of strategies. This activity is helpful in building thinking skills and further developing number sense. They are beginning to see numbers as a picture in their minds that they will carry with them forever.
Square numbers are used frequently in higher math. If they come into contact with them enough now while they are young, they will have no trouble applying this knowledge later on in middle and high school.