1. 31-day months in the Gregorian calendar
2. Counting in binary in Roman numerals
3. Pieces on a chess board
4. The largest countries by population
5. The first presidents of the United States by last syllable of last name
6. The first elements on the periodic table
7. 100 divided by consecutive decreasing integers
8. The possible scores in a tennis match
9. Letters pronounced as words from O to R
10. Seven levels of taxonomic classification
11. Each line is a strict reading of the above line. The first line is read as “one one,” so the second line is “11,” which in turn is read as “two one,” which is written as “21” and then read as “one two one one,” etc.
12. The planets in earth’s solar system starting with the farthest from the sun
13. The numbers correspond to the months of the zodiac sign in those months
14. The first numbers are integers in ascending order. The second number is the number of letters in the first number.
15. The number is the number of sides in the shape that begins with the letter.
16. The postal codes of the 5 biggest United States with their rank number