how do i soile number series quickly

Well, number series is all about practice. The more you practice, the more patterns you get familiar with. Hence, it would be advisable to practice different types of questions. In exams, don't waste too much time on number series questions. If you can identify the pattern in 30 seconds, go for it, else move on and solve other questions. If you have the time left, then you can come back to these questions later.