Top to bottom

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Across
  1. 2. What programmers write to create software.
  2. 4. The number of seasons in a year.
  3. 5. The number of days in a week.
Down
  1. 1. The only even prime number.
  2. 3. A mistake in a system that can cause failure.
  3. 4. The number of fingers on one hand.