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Two Three Ten Sequence

If:
2 3 = 10
7 2 = 63
6 5 = 66
8 4 = 96
9 7 = __

What is the missing number?

f(n, m) = (n + m) × n

e.g. f(2, 3) = (2 + 3) × 2 = 10

Hence, f(9, 7) = (9 + 7) × 9 = 144

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One Two Six Sequence

What is the next number in this series?

1, 2, 6, 42, 1806, ___

To get the next number, multiply the previous number in the series by itself plus one:

n × (n + 1).

For example, to get 6, multiply 2 × (2 + 1)
To get 42 multiply 6 × (6 + 1)

Thus, 1806 × 1807 = 3263442

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Two Two Four Sequence

What number comes next?

2, 2, 4, 12, 48, ___

240. To get the number, multiply the previous number in the series by its position. 48 is in the 5th position, so 48 × 5 = 240

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Next in the Sequence

Here is a series of numbers. What is the next number in the sequence?

1
11
21
1211
111221
312211

13112221

The next number in the series counts the previous numbers. Thus the first number is 1, which is one 1, or 11. To describe 11, you have two 1’s, or 21. Now you have one 2 and one 1, so the next number is 1211. The solution is to continue describing the previous number using only numbers.

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Special Sequence

What is special about the following sequence of numbers?

8 5 4 9 1 7 6 10 3 2 0

The numbers are in alphabetical order.

8 = eight
5 = five
4 = four
9 = nine
1 = one
7 = seven
6 = six
10 = ten
3 = three
2 = two
0 = zero

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