Time unit conversion formula:

1 century = 100 year; 1 year = 65438+ February.

The big months (3 1 day) are: 1 month, March, May, July, August,1month,1February.

Abortion (30 days) includes: April, June, September,165438+1October.

February 28th in a normal year and February 29th in a leap year.

There are 365 days in a normal year and 366 days in a leap year.

1 day =24 hours; 1 =60 points; Minute =60 seconds; 1 =3600 seconds

The progress between two times is 60.

1 = 60 points; 1 = 60 seconds; 1 day = 24 hours; 1 quarter = 15 minutes; Half an hour =30 minutes

Time is converted to minutes (multiplied by 60)

Minute to time conversion (except 60)

Minutes are converted into seconds (multiplied by 60)

Seconds are converted into minutes (divided by 60)

Calculate elapsed time: elapsed time = end time-start time.

"Hours and minutes" exercises in the first volume of mathematics in grade three;

1. The time units we have studied are (), () and (), of which () is the smallest time unit.

2. There are () big squares on the clock face, each big square is divided into () small squares, and there are () small squares on the clock face. The time to walk a big grid clockwise is (); Minute hands occupy a small space (); The time for the second hand to walk the small square is (), and the time for walking the big square is ().

3. The clockwise hand walks a big grid, the minute hand walks () a small grid, and the minute hand walks () a point; The second hand goes once, and the minute hand goes (), which is ().

4, clockwise from the number 3 to the number 9, the elapsed time is (); Minute hand from the number 3 to the number 9, the elapsed time is (); The second hand from the number 3 to the number 6, the elapsed time is ().