89
This is called the Fibonacci sequence. The last two numbers in the sequence are added together to produce the next. Therefore, following 8 and 13 are: 8 + 13 = 21 13 + 21 = 34 21 + 34 = 55 34 + 55 = 89 55 + 89 = 144
It is 21 + 34 = 55
This is a Fibonacci sequence. Each number in the sequence is the sum of the previous two numbers:3+5=85+8=138+13=2113+21=34
1, 1, 2, 3, 5, 8, 13, 21, 34, 55
21 between 13 and 34; it is the Fibonacci numbers where each successive number is the sum of the previous two.