For numbers with 4 or more digits, use commas between every 3 digits.

Don’t	Do
5000 5.999.999	5,000 5,999,999

For decimals, use dots.

Don’t	Do
25,74%	25.74%

For a range of numbers, use the en dash.

Don’t	Do
3-5 days	3–5 days

For a range with a number sign (#), omit space.

Don’t	Do
# 4–6	#4–6

When a number is used as an adjective, use a hyphen.

Don’t	Do
7 day trial	7-day trial