**1. What starts with an E, ends with an E, but only contains one letter?** Answer: An envelope.

**2. What number do you get when multiplying the numbers on a telephone’s number pad?** Answer: Zero (because one of the numbers is zero).

**3. I am an odd number. Take away a letter, and I become even. What number am I?** Answer: Seven (take away the “s” and it becomes “even”).

**4. What is the following number in the sequence: 1, 11, 21, 1211, 111221, 312211, …?** Answer: 13112221 (the sequence describes the last number, so the next one is “one three, one one, two two, two one”).

**5. If two’s company and three’s a crowd, what are four and five?** Answer: Nine (the sum of the numbers).

**6. What is the sum of all numbers on a roulette wheel?** Answer: 666 (the numbers on a roulette wheel add up to 666).

**7. What is the smallest positive number divisible by all the numbers from 1 to 10?** Answer: 2520.

**8. What is the following number in the sequence: 0, 1, 1, 2, 3, 5, 8, 13, 21, …?** Answer: 34 (the sequence is the Fibonacci sequence, where each number is the sum of the previous two).

**9. What is the following number in the sequence: 1, 2, 6, 42, 1806, …?** Answer: 3263442 (the sequence is the product of each number and the previous one plus one).

**10. What is the only number that, when written out, has its letters in alphabetical order?** Answer: Forty.

**11. What is the missing number in the sequence: 9, 16, 23? 37, 44, 51, 58, 65?** Answer: 30 (the sequence adds 7 to each number, except for the missing one).

**12. What is the next number in the sequence: 2, 6, 18, 54, …?** Answer: 162 (the sequence multiplies each number by 3).

**13. What is the missing number in the sequence: 3, 8, 15, 24? 48?** Answer: 35 (the sequence adds 5, then 7, then 9, etc.).

**14. What is the following number in the sequence: 3, 8, 18, 38, …?** Answer: 78 (the sequence doubles each number, then adds 2).

**15. What is the following number in the sequence: 1, 2, 4, 8, 16, …?** Answer: 32 (the sequence doubles each number).

**16. What is the next number in the sequence: 1, 4, 27, 256, …?** Answer: 3125 (the sequence is the nth power of n, so the following number is 5 to the power of 5).

**17. What is the missing number in the sequence: 2, 5, 10, 17? 37?** Answer: 26 (the sequence adds 3, then 5, then 7, etc.).

**18. What is the following number in the sequence: 7, 12, 18, 25, 33, …?** Answer: 42 (the sequence adds 5, then 6, then 7, etc.).

**19. If you have two coins that add up to 30 cents, and one is not a nickel, what are the two coins?** Answer: A quarter and a nickel (if one was a nickel, the other coin would have to be a dime, which would only add up to 15 cents).

**20. What is the following number in the sequence: 1, 3, 6, 10, 15, …?** Answer: 21 (the sequence adds 2, then 3, then 4, etc.).

**21. What is the missing number in the sequence: 5, 10, 19, 34? 85?** Answer: 59 (the sequence adds 5, then 9, then 15, etc.).

**22. What is the following number in the sequence: 1, 3, 9, 27, 81, …?** Answer: 243 (the sequence is the nth power of 3, so the following number is 3 to the power of 5).

**23. What is the following number in the sequence: 2, 5, 10, 17, 26, …?** Answer: 37 (the sequence adds 3, then 5, then 7, etc.).

**24. What is the missing number in the sequence: 4, 9, 19, 39? 159?** Answer: 79 (the sequence doubles each number, then adds 1).

**25. What is the following number in the sequence: 1, 4, 10, 22, 46, …?** Answer: 94 (the sequence doubles each number, then adds 2).