Here is the full list of all 22 Cross Numbers achievements.
Solve a CrossNumber on expert difficulty
Solve 10 CrossNumbers
Complete your first CrossNumber
Solve a CrossNumber on normal difficulty
Ace a CrossNumber on normal difficulty
Solve a CrossNumber on normal difficulty in under 2 minutes
Solve a CrossNumber on normal difficulty in under 1 minute
Solve a CrossNumber on normal difficulty in under 30 seconds
Ace a CrossNumber on expert difficulty
Ace 10 CrossNumbers
Solve a CrossNumber on expert difficulty in under 10 minutes
Solve a CrossNumber on expert difficulty in under 5 minutes
Solve a CrossNumber on expert difficulty in under 2 minutes
Solve 50 CrossNumbers
Solve 100 CrossNumbers
Ace 50 CrossNumbers
Ace 100 CrossNumbers
Solve a CrossNumber on hard difficulty
Ace a CrossNumber on harddifficulty
Solve a CrossNumber on hard difficulty in under 5 minutes
Solve a CrossNumber on hard difficulty in under 2 minutes
Solve a CrossNumber on hard difficulty in under 1 minute