What are odd days? Explain how to find the day of the week for a given date, with an example.

1. 1 · Open in two lines. Odd days are the days left over after complete weeks. Counting odd days from a fixed starting point tells the day of the week for any date.
2. 2 · Draw the odd-day table. [Table: ordinary year 1; leap year 2; 100 years 5; 200 years 3; 300 years 1; 400 years 0. Remainder 0 Sunday, 1 Monday … 6 Saturday]
3. 3 · Leap-year rule. A year divisible by 4 is a leap year, but a century year is a leap year only if it is divisible by 400 (2000 yes, 1900 no).
4. 4 · Steps of the method.
   • Split the completed years into 400s, 100s and the rest.
   • Add the odd days of each block and of the completed months of the given year.
   • Add the date, divide the total by 7 and read the remainder as the day.
5. 5 · Worked example: 15 August 1947.
   • 1,600 years: 0; 300 years: 1; 46 years: 11 leap + 35 ordinary = 57, which leaves 1.
   • January to July 1947: 16, which leaves 2; 15 days of August leave 1.
   • Total 0 + 1 + 1 + 2 + 1 = 5 → Friday.
6. 6 · Use in competitive exams. SSC, railway and placement tests ask day-of-the-week and leap-year questions; the odd-day table answers them in a few lines.
7. 7 · Close in one line. Count odd days, not days: the remainder after dividing by 7 names the weekday.

Scoring tip: Draw the odd-day table first; then the worked example takes only four lines and every step earns marks.