Complete the series: 7, 13, 21, ______, 43.
Complete the series: 7, 13, 21, ______, 43.
Explanation
The series is formed by adding 6, 8, 10, ... to the previous term, so the next difference should be 12, making the next term:7 + 6 = 13
13 + 8 = 21
21 + 10 = 31
31 + 12 = 43
Therefore, the completed series is: 7, 13, 21, 31, 43.