## 4 5 6 6

What digit should appear after this list of numbers?

4 5 6 6 5 4 4 2 ?

7. The digits represent the number of letters in each word of the puzzle. “What” has four letters, “digit” has five letters, “should” has six letters, etc. The last word is “numbers” which has seven letters.

Posted in Brain Teasers
Tagged with

A A D F J J J M M N ?

What comes next in the series?

O S. The series contains the first letter of each month in alphabetical order (April, August, December, February, January, July, June, March, May, November). O and S represent the remaining 2 months, October and September.

Posted in Brain Teasers
Tagged with

## 5 25 325 4325

Given

1 = 5
2 = 25
3 = 325
4 = 4325

What does 5 equal?

54325. Rather than being a mathematical solution, the answer is derived by prepending (putting in front of) the value on the left side of the equation with the previous answer. So for 3 you take 25, the previous answer, and put 3 in front, giving you 325. Then you put 4 in front to get 4325 and lastly, put 5 in front to get 54325.

Posted in Brain Teasers
Tagged with

## 011 235 Sequence

011 235 813 213 ???

What comes next?

455. The numbers are from the Fibonacci sequence in groups of 3. The next numbers in the series are 34 (the 3 was already used in 213) and 55.

Posted in Brain Teasers
Tagged with

## O T T F F

What letter comes next?

O T T F F S S

E (one, two, three, four, five, six, seven eight)

Posted in Brain Teasers
Tagged with

## O S C Sequence

O, S, C, Y, S, B, T, D, ?

What is the next letter in the sequence?

E. Oh say can you see, by the dawn’s early light.

Posted in Brain Teasers
Tagged with

## Three Two Three Sequence

What number belongs at the beginning of this sequence?

?, 3, 2, 3, 9, 2, 4, 8, 4, 3, 7, 6

3 ½.

If you break up the numbers into groups of 4, a,b,c,d, then 2 × |a – d| = |b – c|.

9 2 4 8 → 2 × |9 – 8| = |2 – 4|, or 2 × 1 = 2
4 3 7 6 → 2 × |4 – 6| = |3 – 7|, or 2 × 2 = 4, so
n 3 2 3 → 2 × |3 ½ – 3| = |3 – 2|, or 2 × ½ = 1;

I’m not sure this is the correct solution, but it’s the best I’ve found so far. Email me if you know of a better one.

Posted in Brain Teasers
Tagged with

## Two Three Four Fifteen

What is the missing number?

2 3 4 15 12
3 4 5 28 20
4 5 6 45 30
5 6 7 66 42
6 7 8 ?? 56

91. To get the number in the fourth column, you add the numbers in column 1 and 2, then multiply by the number in column 2. f(n,m) = (n + m) * m
For example, f(2,3) = (2 + 3) * 3 = 15. Thus f(6,7) = (6 + 7) * 7 = 91

Posted in Brain Teasers
Tagged with

## Six Nine Twenty-Seven

What is N?

6, 9, 27, 54, N, 2241

675.

The next number in the sequence is n squared minus m or f(n,m) = n2 – m
f(6,9) = 62 – 9 = 27
f(9,27) = 92 – 27 = 54
f(27,54) = 272 – 54 = 675
f(54,675) = 542 – 675 = 2241

Posted in Brain Teasers
Tagged with

## Eight Eleven Five Sequence

Which two numbers are missing and where do they go in the sequence?

8, 11, 5, 14, 1, 7, 6, 10, 13, 3, 12, 2

The missing numbers are 4 and 9. The list is sorted alphabetically by the English spelling of the numbers, so four belongs after five and nine comes after fourteen.

Posted in Brain Teasers
Tagged with