It was not discovered, it was created!
28 months = 852.2 days.
All months have at least 28 days
All 12 months have "at least" 28 days. Only February has exactly 28 days, except in leap year.
They all do because its saying how many months have 28 days not what months only have 28 days
All twelve months have at least 28 days, February has exactly 28 days except for leap years.
ALL months have 28 days! Should have said "Why does February have 28 days and some have 31?".
Technically all 12 months have at least 28 days in them. However, I suspect you are actually asking how many months have only 28 days. In that case, February is the only month to have only 28 days in its month (except for leap year when it has 29 days).
852.23 days
A month can be an interval of 28, 29, 30, or 31 days. (Look at a calendar.) 640 days = 20.6452 months of 31 days. (rounded) 21.3333 months of 30 days. (rounded) 22.0690 months of 29 days. (rounded) 22.8571 months of 28 days. (rounded)
The only month that has 28 or 29 days is February.
February has 28 days
12 months have 28 days. The only one that has a max of 28 days is February, except in leap years.