The calendar helps us see the dates, and therefore the day of the week, of the same dates.

We know that there are 12 months in a year. The months of January, March, May, July, August, October and December have 31 days. The months of April, June, September and November have 30 days. The month of February has 28 or 29 days.

There are 7 days in a week. 1 day corresponds to 24 hours.

We can count the number of days between the two dates given. We take the start day and the last day into account in our calculation.

Calculation of the number of days between two specified dates.

Riana lived in her grandmother’s house from 15th July to 12th August. Now did Riana stay with her grandmother for a long time?

Days in July = 31 – 15 = 16 + 1 = 17

Days in August = 12

Total number of days = 17 + 12 = 29

Riana stayed with her grandmother for 29 days.

When calculating days, there are times when we include the first and the last day in the calculations. To find the number of days Riana’s stay we subtract 15 from 31 (since there are 31 days in July) and then add 1 because; we want to take 15th July in our calculation.

What will be the date 26 days after Mach 19.

Days in March = 31 – 19 = 12

Days in April = 26 – 12 = 14

The date 26 days after March 19 is April 14.

In this example, we don’t need to include March 19th in the calculation because the date is requested after March 19th.

What was the date a fortnight before 10th October?

Days in October = 10

Days in September (previous month) = 14 – 10 = 4

30 – 4 = 26

The date a fortnight before October 10th was October 26thth September.

14 days = 14 days.

This calculation is done in three steps.

1. Days in October.

2. Days in the previous month (in this case September).

3rd Total Number of Days in September – Required number of days in September.

In this example, too, the days before October 10 must be counted. Therefore, we do not include October 10 in our calculation.
When we count the number of days before or after a certain date, we do not take the given date into account in our calculation, but instead start with the day before or after the given date.

1. If yesterday was Friday, the day after tomorrow will be bw:

(i) Thursday

(ii) Friday

(iii) Saturday

(iv) Monday

1. (iv) Monday

2. Nancy went on a trip with her family. They came back after 5 weeks 4 days. How many days did you spend on the trip?

(i) 39 days

(ii) 37 days

(iii) 40 days

(iv) 24 days

2. (i) 39 days

Related concepts

Units for length measurement

Measuring device

How to Measure the Length of a Line Segment

Circumference of a figure

Unit of mass or weight

Examples of units of mass or weight

Units for measuring capacitance

Examples of capacitance measurement

Timing

Antemeridian (am) or Postmeridian (pm)

What time is it?

Time in hours and minutes

24 hours clock

Time units

Examples of time units

Duration

calendar