Time

365+1/4-3/400=365.2425

starting with a non leap year 7 calenders

starting with a leap year 7 calendars

starting with 2001, takes 28 yrs to use all of the calendars

There are an almost infinite number of calendars possible.

Calendars are constructs for the purpose of counting periods of time or combinations of periods. The purpose of the counting varies so the periods chosen can be varied, Those period may be based on some astronomical phenomena or on something entirely arbitrary, or a combination of both.

Keeping time, in the days before mechanical clocks.

0.4 hour = 0.4 x 60 = 24 minutes.

1000 milliseconds = 1 second so am milliseconds = am/1000. Simple!

Babylonians and Egyptians.

Milligram, Centigram, Decigram, Gram, Dekagram, Hectogram, Kilogram. A good way to remember the prefixes is the phrase "King Hector Died Unexpectedly Drinking Chocolate Milk." (The 'U' stands for units without prefixes: gram, meter, liter.)

A fortnight

The SI unit of time is the second (s), which is defined based on the vibrational frequency of the cesium atom in atomic clocks. It is used as the base unit for measuring time intervals in various scientific and everyday applications.

The closest that I can say is one minute and six hundred and thirty eight thousandths of a minute (rounded slightly down)

Two days is about 172,800 seconds.

There are 3,600 seconds in an hour. This is because there are 60 seconds in a minute, and 60 minutes in an hour.

3 mins is 180 seconds, i.e. 180,000 milliseconds. 180,000/13 is 13846.15 times.

Generally speaking it is not necessary to capitalize decades unless it occurs at the start of a sentence.

There are 604,800 seconds in a week.

A millisecond is one thousandth of a second.

90 days = 2 160 hours = 129 600 minutes = 7 776 000 seconds

1 second = 1000 milliseconds so 35 seconds = 1000*35 = 35000 milliseconds. Simple!

194 minutes = 3 hours 14 minutes

60+60+60=180 so the answer is 180 seconds in three mins

100 minutes.

888 minutes = 14 hours 48 minutes

one minute and thirtyeight,twentynine hundredth of seconds

That date was September the eleventh, the time was within the twenty four hour period of that date, the day can be any day depending on the year
If you are referring to 9/11/2001 then it was a Tuesday, the time cannot be given precisely as you do not state the particular incident, there were several.

because each culture has different ways and differnet calenders could be American, Mayan, iztec, and Inca