Wyoming Math 3.MD.7a

Math3rd GradeMeasurement and Data

The Standard

Relate area to the operations of multiplication and addition. Find the area of a rectangle with whole-number side lengths (dimensions) by multiplying them. Show that this area is the same as when counting unit squares.

2023 Wyoming Mathematics Content and Performance Standards · Geometric measurement: understand concepts of area and relate area to multiplication and to addition.

Teacher's field guide

What This Standard Means

What Students Need to Do: Students count the unit squares that cover a rectangle and use its rows and columns to write a multiplication equation for its area. They connect repeated addition of equal rows to the same total.
What Mastery Looks Like: Given a 4-by-6 grid, a student counts 24 unit squares and writes 4 × 6 = 24 square units. They can explain that 6 + 6 + 6 + 6 gives the same area.
Common Misconceptions: Some students add all four side lengths, finding perimeter instead of area. Others count grid lines instead of squares or write 4 + 6 = 10 for a 4-by-6 grid.
How to Assess It: Give students a rectangle with 3 rows of 5 unit squares. Ask: How many square units cover it? Show a count, a repeated addition equation, and a multiplication equation.

Lesson moves

Ways to Teach It

Have pairs build 2-by-7 and 4-by-6 rectangles with square tiles, then count the tiles and write multiplication equations.
Show a 3-by-6 grid and ask, "Why does 6 + 6 + 6 give the same area as 3 × 6?"
Play area match with cards showing tiled rectangles, repeated addition equations, and multiplication equations; students collect matching sets.
Cover a 3-by-5-inch index card with square-inch tiles, then count rows and columns and multiply to find its area.

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