It’s great, to introduce this formula to find the Days for the 10,000 years. You can calculate the day by mentally

Day formula→ (D+M+Y+[y/4]) mod 7

Here, D= Date

M=Month

Y= year’s last two digits

Y/4= year’s last two digit divide by 4 and the quotient (if decimal, consider the integer only)

Example: 1

Let us take my Friend’s Birth Day 30-05-2011

Day =(D+M+Y+[y/4])mod 7

=(30+2+11+[2])mod 7

=45 mod 7 (Divide 48 by 7 then the remainder 3).

= Remainder 3

Hence, my Son’s Birthday on Monday

(Note: The Birth year is more than 2000, therefore, consider the table -2 and category -2)

Explanation:

Step 1: Date (30)

Step 2: For the month of May Number identifies form the Table-1(2)

Step 3: Birth year of last two digits (11)

Step 4: Birth year last two digits divide by 4 and take only the quotient to leave the remainder

Step 5: Sum of all the number (30+2+11+2) and divide by 7,

Compare to the Table-2 with remainder and find the Day [45/7 then the remainder is 3, therefore, the Day is Monday]

Example: 2

Let us see, for the date 14/07/2019 is on which day

Day= (D+M+Y+[y/4]) mod 7

= (14+0+19+[4])mod 7

= (37/7 and the remainder is 2]

Hence,

Compare to the Table-2 with remainder and find the Day [37/7 then the remainder is 2, therefore, the Day is Sunday]

the Day is Sunday

Exercise: 1

Zambia Independence Day is On 24 October 1964 If 24th October falls on which day?