Drawing number into triangular dot pattern and making a square (with same numbers of dots in rows and columns) will give a square number. Similarly, 16 = 42 = 32 + (3 + 3 + 1), 25 = 52 = 42 + (4 + 4 + 1) and so on.
Kelsey must spend less than or equal to $65. The expression 5.50b+7.5 is correct Kelsey able to purchase 10 books. On the end Kelsey can spend $2.50 to purchase small present (calendar or book for notes)
