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Curriculum › Math ›Grade 6

Grade 6 Math · Level 3, Expressions, Equations & Inequalities

Use Formulas with Variables

How the lesson starts: Use Formulas with Variables

  1. Treehouse plans

    Hi, builder! Kai and Rosie are building a treehouse. Their plans are full of formulas, like A = lw, P = 2l + 2w and d = rt. A formula is a rule with letters. Put in the numbers you know, and it hands you the one you need!

  2. Floor area

    First, the floor. Its length is l = 8 feet and its width is w = 3 feet. The area formula is A = lw, which means l times w. Count the squares: 3 rows of 8. So A = 8 × 3 = 24 square feet.

  3. A railing all around

    Rosie wants a railing around a deck 7 feet long and 3 feet wide. Use P = 2l + 2w: two lengths plus two widths. 2 × 7 = 14, and 2 × 3 = 6. So P = 14 + 6 = 20 feet. Watch out: double both the length and the width!