Problem
Reasoning · Grade 2-2 Multiplication Facts
One tile per number
One number per tile means 12 tiles.
If every region holds one and only one number, then pointing at each number points at one tile - so just count the numbers.
2.OA.C.4Make A Systematic ListAdd up the tile areas
A tile covers its own number of cells, so the total area is the sum of the numbers.
Each tile's cell count is its number, so the grand total of cells is simply all the numbers added together.
3.OA.A.3Identify SubproblemsMatch the total to the grid area
That sum is 64 = 8 × 8, matching the grid exactly.
Area of a rectangle is rows times columns; if the pieces' areas add up to the whole rectangle's area, the pieces can fit together perfectly.
3.MD.C.7Draw A DiagramIf the tile areas add up to exactly the rectangle's area, the tiles can fill it with no gap and no overlap.
Why?
A rectangle's area is its rows of equal cells counted up, which is what multiplying its side lengths does.
Why?
Pieces that cover the whole with no gap and no overlap must have areas that add back to the whole, so a mismatch would prove a tiling impossible.
Count the numbers to count the tiles, then add the numbers up - if they total the grid's cells, every rectangle fits like a perfect puzzle!
- One tile per number
- Add up the tile areas
- Match the total to the grid area