Measures of time
A.M. and P.M.
* The time between 12 o'clock midnight and 12 o'clock noon is called a.m. (ante meridian)
* The time between 12 o'clock noon and 12 o'clock midnight is called p.m. (post meridian)
Example: 10 o'clock in the morning is written as 10 a.m. and 10 o'clock in the night is written as 10 p.m.
1 day = 24 hours.
1 hour = 60 minutes.
1 minute = 60 seconds
Example: 1.
How many hours are there in 9 days?
Solution: 1 day = 24 hours.
= 9 days x 24 hours
= 216 hours; Answer
Example: 2.
Convert: 18 days 11 hours into hours
Solution: 1 day = 24 hours.
= 18 x 24 hours + 11hours
= 432 hours + 11hours
= 443 hours; Answer
Example: 3.
Convert: 2 days 2 hours 15 minutes and 30 seconds into seconds.
Step:1. 1 day = 24 hours.
= 2 x 24 hours + 2 hours
= 48 hours + 2hours
= 50 hours.
Step:2. 1 hour = 60 minutes
= 50 x 60 minutes + 15 minutes
= 3000 minutes + 15 minutes
= 3015 minutes
Step:3. 1 minute = 60 seconds
= 3015 minutes + 30 seconds
= 3045 seconds Answer
Calendar:
* We have already learnt that there are 7 days in a week.
Monday,
Tuesday,
Wednesday,
Thursday,
Friday,
Saturday,
Sunday.
Thus, 1week = 7 days
A year has 12 months called calendar months.
January,
February,
March,
April,
May,
June,
July,
August,
September,
October,
November,
December.
Number of days in the month:
* April, June, September, November - 30 days each.
* January, March, May, July, August, October, December - 31 days each.
* February - 28 or 29 days.
* There are 365 days in a year.
* Leap year: if a year number is actually divided by 4 then it is called a lap year. In a leap year, February has 29 days. So in a leap year there are 366 days.
Example: 2.
How many days where there in February 1988?
Solution: Divide 1988 by 4.
= 4) 1988 (497
The year 1988 is actually divisible by 4. so it was a leap year. February, 1988 had 29 days.
1 month = 30 days.
1 week = 7 days.
1 day = 24 hours.
1 hour = 60 minutes.
1 minute = 60 seconds.
1 year = 365 days.
A leap year = 366 days.
In a leap year, February has 29 days.
Example: 4.
Convert 6 months 15 days into days.
1 month = 30 days
8 months = 8 x 30 days + 15 days
= 240 days + 15 days
= 255 days; Answer
(A) Fill in the blanks.
1) .......... days = 1week.
2) ........ months = 1year.
3) A leap year has ....... days.
4) A non leap year has....... days.
5) In a leap year February has...... days.
6) ......... days = 1month.
7) 24 hours = ....... day.
8). ....... minutes = 1 hour.
9) 60 second = 1 minute.
10) In a leap year, February has ..... days.
(B) Give the answer to the following questions.
1) write down the names of the months which have 30 days.
2) write down the names of the months which have 31 days.
3) How many minutes are there in 1 hour?
4) How many seconds are there in 1 minute?
5) How many rounds does the minute-hand complete in a day?
6) How many rounds does the hour- hand complete in a day?
7) How many minutes are there in 1 hour and 20 minutes?
8) Draw the hands on the clock to show both the timings, I go to school at 8:30 a.m. and come back at 1:50 p.m.
