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Grade 3 Math · World 8: Area and Perimeter Park · Level 73
Break Apart a Rectangle
Split a rectangle to find its area.
Warm-up, learn, try it together, practice, then a quick check. About 15 minutes.
What children learn in Level 73
- This rectangle is 4 squares tall and 7 wide. 4 × 7 is tricky? Break the 7 into 2 and 5, and you get two easier rectangles.
- The purple part is 4 × 2, which is 8. The green part is 4 × 5, which is 20. Together: 8 + 20 = 28.
- We can write it as 4 × (2 + 5). The parentheses say add 2 and 5 first, to get the whole side. It's the same area!
- Split a long side into numbers that are easy to multiply, like 5 and what's left.
Georgia's K-12 Mathematics Standards:
- 3.GSR.7.3 — Discover and explain how area can be found by multiplying the dimensions of a rectangle.
- 3.PAR.3.3 — Apply properties of operations (i.e., commutative property, associative property, distributive property) to multiply and divide within 100.