Number systems

123456789
Across
  1. 2. 1,2,3……
  2. 5. 1,3,5,7,….
  3. 7. 1/2 3/5
  4. 9. 0,1,2,3….
Down
  1. 1. 2,4,6,8….
  2. 3. 2x
  3. 4. 2x + 2
  4. 6. root 2
  5. 8. 2x + 3y + 5