Systems of numeration roman numerals,large no’s and the four operations and measurement

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Across
  1. 2. What is the sum of the smallest 2 digit no and the smallest 1 digit no
  2. 4. What is the number (clue in roman no’s:XXI)
  3. 5. What is the successor of 165999
  4. 7. What is the successor of 499999 but the predecessor of 500001
  5. 8. 456678 in international system of numeration
  6. 10. What is 200 kg in g
Down
  1. 1. What is 8 multiplied by 8 plus 7
  2. 3. What is 10l in ml
  3. 4. What is the successor of 1,99,999 in international system
  4. 5. Which is bigger 165845 or 165854
  5. 6. What is XXXIV in figures
  6. 9. What is the meaning of L in roman numbers