Here are some of the famous Greek mathematicians.
"His followers, Pythagoreans, believed that math was the basis for all things in life. They studied a series of numbers called triangular numbers. They laid the numbers out in rows of stones and saw that they always formed triangles."
"They also discovered that there were four figures that had all sides and angles equal. They called them the Platonic bodies, after Plato (another famous thinker and teacher in Greece)." I found a template at Math is Fun to make the 5 platonic bodies: pyramid (4 sides), cube (6 sides), octahedron (8 sides), dodecahedron (12 sides), icosahedron (20 sides). I had a little trouble making the 20 sided one.
"Greek mathematicians also discovered the pengaton, a five-sided shape. That helped them make up a pentacle, which is a five-pointed star. The Pythagoreans used the pentacle as their secret sign to each other. They studied the pentacle because it could be make with a 'never-ending line. Notice that the outside of the pentacle forms a pentagon and so does the inside of the pentacle. "
Discovered prime numbers - To find prime numbers make a chart from 1-100 and cross out any numbers that can be divided evenly by 2, 3 or 5. The ones that are left are the prime numbers
Sieve of Eratosthenes