Math puzzle

12345678910
Across
  1. 3. 4 sided polygon
  2. 4. result of addition
  3. 5. 3D shape with 6 faces
  4. 7. Number that divides exactly into another number
  5. 8. A number less than 0
  6. 9. a part of a whole
  7. 10. Longest side of right triangle
Down
  1. 1. Symbol used to represent unknown value
  2. 2. distance around circle
  3. 6. Result of multiplication