This site offers many games on the calculation of the perimeter and area of the square, the rectangle, and the circle.
Online math games : geometry | perimeter and area calculation | educational games | numbers | numerical calculation | Middle School | 4th 5th 6th Grade | multiplication | 11 year old | 12 year old | 6th Grade | 7th Grade | junior | mental calculation | games for kids | games and quizzes corrected