Here the rectangle has 9 rows of 9.
We may consider 9 rows of 9 squares.
So the area must be 9× 9
Now if Finn Imagines 1 more row of 9 squares.
It makes it 10 rows of 9 squares each.
so 10 rows of 9 squares each makes is 10 ×9 = 90
Now we subtract the 9 square row we added
We get
90 - 9 = 81
Now these 81 squares shall be 9 rows of 9
Hence the area shall be 9 × 9 = 81.
This shall be more comfortable for Finn to calculate the area of the rectangle.
