Odd Day -

No. of odd day	0	1	2	3	4	5	6
day	Sun.	Mon.	Tues.	Wed.	Thur.	Fri.	Set.

Leap year

every year which is divisible by 4

366 days / 7 = 52 weeks + 2day

Ordinary year

every year which is not divisible by 4

366 days / 7 = 52 weeks + 1day

100 year

76 odinary year + 24 leap year

(76 * 1) = 76 + (24 * 2) = 48 = 124 / 7 = 17 + 5 reminder

5 odd day

200 year

5 odd day * 2 = 10 odd day / 7 = 1 + 3 reminder

3 odd day

300 year

5 odd day * 3 = 15 odd day / 7 = 2 + 1 reminder

1 odd day

400 year

0 odd day

Q1.) What was the day of the week on 28 March 1722?

STEP 1 :

First of all substract 1 with the year

1722 - 1 = 1721

STEP 2 :

Divide the year with 400 to check the number of leap year

1721 / 400 = 121

STEP 3:

100 years = 5 odd days so

121 year & 1 Jan to 28 March 1722

1 * 100 = 1 * 5 = 5 odd day

STEP 4:

Now again check leap year

21 year = 21 / 4 = 5 leap year

and subtract the leap year with 21 to calculate ordinary year

21 year = 5 leap year + 16 odinary year

STEP 5:

As aboe discuss

1 leap year = 2 odd day

1 ordinary year = 1 odd day

5 * 2 + 16 * 1 = 26

Now divide the total days with 7 and reminder will be odd days

26 / 7 = 5 odd days

STEP 6:

1 Jan to 28 March 1722

Number of Days in 1722
Jan	30
Feb	28
Mar	28
Total No. of Days	86

STEP 7:

Now divide total numbers with 7 to calculate odd days

86 / 7 = 2 odd days

Now calculate total number of odd days

Total odd days = 5 + 5 + 2 = 12 odd days

STEP 8:

Now divide total odd days with 7 and remainder will be odd days

12 / 7 = 5 odd days

Now from above table 5th day of week Friday

On 28 March 1722 day will be Friday