Texas Math Models

Try “number line” or “4.5D”

Add one of each, then double

12 + 7 + 12 + 7 = 38 units G4

one length and one width make half the trip67127half wayhalf way2 × (6 + 7)2 × 13 = 262 × (12 + 7)2 × 19 = 38the green sides are half the total; double them

How this one works

How

add one long and one short side, then double it.

Best when

you want the fewest steps.

seen one of these on a test? See it on a real question: TEKS 3.7B, perimeter, and a missing side, or TEKS 4.5D, perimeter and area of rectangles.

The same problem, other ways