Which of the following numbers will replace the question mark (?) in the given series?
9, 10, 18, 45, 109, ?

Given series: 9, 10, 18, 45, 109, ?

Step 1: Find the differences between consecutive terms

10 – 9 = 1

18 – 10 = 8

45 – 18 = 27

109 – 45 = 64

The differences 1,8,27,64 appear to be cubes of consecutive numbers

Following this pattern, the next difference should be: 125

Add the next difference to the last term in the series:

109 + 125 = 234

Conclusion: The number that will replace the question mark is 234.