Meredith's number puzzle

123456789
Across
  1. 2. the square root of 10
  2. 3. 5 to the second power plus 4 to the second power
  3. 7. 10^5
  4. 9. 23 to the second power
Down
  1. 1. 6/12 to the second power
  2. 4. 10 squared
  3. 5. 4x7^2x5
  4. 6. 67 to the 2nd power
  5. 7. 5 to the 3rd power
  6. 8. 2/4 simplified