Bigger, Better, Best by Marsha Winborn, Stuart J. Murphy (2002, Paperback, Illustrated)

Jenny and Jeff are driving their little sister, Jill, crazy, and now that the family is moving into their new house it's worse than ever. Who'll have the bigger window? Who'll have the bigger bedroom? How can they measure the space so that they'll know for sure?

Jenny and Jeff must calculate area to settle their debate. This simple geometry concept will prove once and for all whose room is bigger -- but maybe Jill can show her squabbling siblings that bigger isn't always better!