Number plugging strategy?

Well; you are asking a very generic question. I am basically pointing at that I use number plugging strategies for DS questions in a different way than I do for problem solving. Even within problem solving, I plug numbers very frequently to solve rate problems, percentages and ratios.

But I'd say this:

1. In any problem if you had to plug the numbers and evaluate the answer choices, you could start working with 0, 1, -1, 2 and -2. I read this tip in some book 9do not remember which one) and if your answer is not deducible from just these, go ahead to involve -1/2 and 1/2 as well. This strategy is useful in DS questions especially.

2. For percent questions, your choice depends on what exact numbers are used in the question. For example in a question that relates to finding successive percentages (rebate of 20% first and then 25%), I start with 100. In other cases where we have multiple percentages (20% of people researched had one habit and 30% had another) kind of questions, I start with 1.

3. In rate and work questions, I use the Least Comm Multiple. If 3 men work on some task 20 hours and 4 people do the same work in 10 hours, I will try to find the LCM of 60 and 40 and then assign the unit rate of work as 2 units per woman per hour and 3 units per man per hour.

I am not sure if you are asking for anything more. But in case you need more detail, shoot back.

Regards
Rahul