Vertices is the word for more than one vertex.

vertex is where two sides meet.

solution:

Next, count the vertices all around this shape.

5 is less than 6.

So, this shape has fewer vertices.

solution:

Count the sides of both shapes.

First, count the sides all around this shape.

Next, count the sides all around this shape.

3 is less than 6.

So, this shape has fewer sides.