Greatest Integer Function

[  ] sign is
the greatest integer function sign.

[a] means
the greatest integer
that is less than or equal to a.

Draw three lines like this.

Write 2.5
at the left side of the middle line.

2.5 is between two integers
2 and 3.

So write 2 and 3
at the left side of the top and bottom lines.

The bottom number, 2, is [2.5].

So [2.5] = 2.

So 2 is the answer.

The greatest integer function of an integer
is itself.

So [6] = 6.

So 6 is the answer.

Draw three lines like this.

Write -π
at the left side of the middle line.

-π = -3.14...

-3.14 is between two integers
-3 and -4.

So write -3 and -4
at the left side of the top and bottom lines.

The bottom number, -4, is [-π].

So [-π] = -4.

So -4 is the answer.