Number Differences free demo
ATSA-style section 1 of 7 · about 2 minutes · Numeric keypad (on-screen keypad on touch devices)
About the Number Differences section
Number Differences is usually the first thing candidates meet on the Air Traffic Skills Assessment. A single digit from 1 to 9 appears, then another, and for each new digit you enter how far it is from the previous one. There is no time to write anything down, and the next digit arrives whether you are ready or not.
The skill is holding one number in mind while you process the next, which is exactly the kind of quick, repeated mental bookkeeping a controller does all shift. Most people find the first block awkward and improve quickly once the keypad movement becomes automatic.
Our version generates fresh sequences every run, so you cannot memorize it. Practice mode gives feedback on every item; timed mode runs at a realistic pace and shows your accuracy and response times at the end.
Tips from practice
- Keep your fingers resting on the keypad so you are only ever moving one finger.
- Say the previous digit silently as you look for the next one; it stops the chain from slipping.
- If you miss one, drop it and pick up the next pair. Chasing a lost item costs you two.
Common questions
- Is the difference always positive?
- Candidate reports describe entering the size of the difference between the two digits. Our drill follows that convention and explains it in the tutorial before you start.
- Can I practice this on a phone?
- Yes. An on-screen keypad appears on touch devices, although a physical numeric keypad is closer to the test center setup.
This demo is independent practice built from public descriptions of the ATSA. It is not affiliated with or endorsed by the FAA, and it is not identical to the real test.