Lesson objective: Apply understanding of measuring area by counting square units to solve problems.
This lesson provides an opportunity for students to apply their knowledge and understanding of measuring area with square units to a reallife situation. Students are asked to use square tiles and graph paper to find all possible rectangular pond designs large enough for 24 fish, decide which design uses the least number of tiles around the border of the pond, and find which design has the least total area and therefore takes up the least amount of space.
Key Concept students will use:

Area is an attribute of plane figures describing how much twodimensional space is covered by the figure.

Square units or unit squares (that cover a figure without gaps) can be used to measure the area of a figure, which is said to be n square units.
Skills students will use:
 find all possible rectangular arrays for a given number of objects (Grade 3, Unit 1)
Students engage in Mathematical Practice 4 (model with mathematics) as they use square tiles and drawings on graph paper to represent and find the area of different rectangular pond designs.
Key vocabulary:
 area
 square unit
 tiling
 unit square
Special materials needed:
 centimeter graph paper
 square tiles (if none are available there are printable square tiles in Additional Materials)