Math fun

12345678
Across
  1. 2. A polygon having 6 sides
  2. 3. One piece out of 4 equal pieces
  3. 6. I have three faces, 2 edges and no vertices
  4. 7. A closed figure with three sides
  5. 8. The amount left over after equal division
Down
  1. 1. One hundred years
  2. 4. The terms used to represent the numbers that are being added
  3. 5. Inverse of division
  4. 6. A closed curved figure