Number crossword

123456789
Across
  1. 3. A popular number puzzle game.
  2. 4. A difficult task that tests ability.
  3. 7. To find the answer to a problem.
  4. 8. An activity engaged in for amusement.
  5. 9. A single numeral from 0 to 9.
Down
  1. 1. A game or problem designed to test ingenuity.
  2. 2. The science of numbers and their operations.
  3. 4. A piece of information used to find an answer.
  4. 5. The pattern of squares for placing numbers.
  5. 6. The reasoning process used in many puzzles.