121
If the last number is 1/3 (it should be), the next number is 5 and 1/3
Fibonacci sequence Fibonacci sequence
The spacing is 6 1+6=7 7+6=13 13+6=19 19+6=25 so the missing number in the sequence is 13
It is: 1 and 13/40
21
If the last number is 1/3 (it should be), the next number is 5 and 1/3
40.
Fibonacci sequence Fibonacci sequence
The spacing is 6 1+6=7 7+6=13 13+6=19 19+6=25 so the missing number in the sequence is 13
18
It is: 1 and 13/40
10 (between 7 and 13)
21
The next number in the sequence is 18. It's +1, +2, +3, +4, ....
Start with the numbers 1 and 1. After that, every number in the sequence is the sum of the previous two numbers. Thus, the sequence starts with: 1, 1, 2, 3, 5, 8, 13, ...
The pattern appears to be: subtract 6, add 17, subtract 14, add 9, subtract 7. Following this pattern, the next number should be obtained by adding 3 to the last number in the sequence, which is 6. Therefore, the next number in the sequence is 9.
34. Each number is the sum of the two preceding numbers. This is called the Fibonacci Sequence.