The First Four Add Number Each Divisible By 3

The first four add number each divisible by 3

 

Answer:

3, 9, 15, 21

Step-by-step explanation:

Pattern of the multiples of 3: odd-even-odd-even and so on.

Multiples of 3: 3, 6, 9, 12, 15, 18, 21, 24, 27, 30 and so on.