Area/Perimeter
Complex Area/Perimeter Practice
Area Practice
https://www.homeschoolmath.net/worksheets/area_perimeter_rectangles.php
https://www.ixl.com/math/grade-4/area-and-perimeter-word-problems
https://www.mathgames.com/skill/4.17-relationship-between-area-and-perimeter
https://www.math-only-math.com/areas-of-irregular-figures.html
http://www.softschools.com/math/geometry/topics/the_area_of_irregular_figures/
https://www.ixl.com/math/grade-4/find-the-area-or-missing-side-length-of-a-rectangle
https://www.ixl.com/math/grade-4/area-of-complex-figures-with-all-right-angles
https://www.youtube.com/watch?v=e-znfToKlxQ