1. Read out the numbers given.
2. Notice the pattern in the sequence of numbers.
3. Guess the number that should come next.

Look at the numbers in the above sequence. Here the difference between one number to the next is 5, therefore, it is skip counting by 5. That is, to each number we have to add 5 to get the next number.

In the above example,
129-124 = 5
134-129 = 5
Answer : 139