The 5*5 grid shown contains a collection of squares with sizes from 1*1 to 5*5. How many of these squares contain the black square?
+122 Well, let's take a deeper look.
It's in the 5×5 square.
it's in all 4 of the 4×4 squares.
it's in all 9 of the 3×3 squares.
It's in 4 of the 2×2 squares.
It's in 1 of the 1×1 squares.
That would leave us with a total of 19 squares.
