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?

Guest Dec 29, 2020

#1**0 **

Well, let's take a deeper look.

It's in the \(5\times5\) square.

it's in all \(4\) of the \(4\times4\) squares.

it's in all \(9\) of the \(3\times3\) squares.

It's in \(4\) of the \(2\times2\) squares.

It's in \(1\) of the \(1\times1\) squares.

That would leave us with a total of \(\boxed{19}\) squares.

cryptoaops Dec 29, 2020