Many times people are mislead with math and numbers by the way that the information is presented or unfolded to them.
Entire context can be vastly skewed based on how quantitative information is presented, what is included, what is not included, emphasis on one thing over another, all can potentially mislead the viewer.
Example:
We hear so much about the Iraq war and such but not so much about deaths on US highways or suicide.
4500 deaths in Iraq from 2003 to 2012
30,000 died on US highways last year
30,000 died from suicide last year
You rarely hear these statistics side by side but in the same amount of time as the Iraq war took 4500 US lives, the highways and suicide took 540,000 lives.
The whole point of this is just illustrate that you should always be a detective during the presentation of quantitative data, look at motives, look at what is being left out, ask why something is being emphasized and what is being de-emphasized and ask why?
It is easy to be mislead or to mislead with quantitative data.
My friend who raises and markets exotic animals is a great example of this. When someone learned he had a pair of alligators they asked what good they were. He said that he had not had a single rattlenake on his property since acquiring the gators. To the best of his knowledge, he had NEVER had a rattlesnake on his property and the gators in the large stock tank couldn't get out to meet up with one in the first place. Nevertheless, the fellow who asked the question was impressed.
By the way, figures don't lie, but, liars figure!
Best book I ever saw on presenting data was Visual Explanations by Edward Tufte. He may have another one also.
He shows some creative graphs and pictorials presenting very complex data in a way that you are immediately led to understand it. Many were selected as the best in history at doing what they did.
He also has a very interesting comparison of the actual somewhat confusing presentation of prior seal failure data on the morning of the Challenger space shuttle launch, and the same data presented in a way that would have led anyone to postpone the launch.
If this topic interests you, I suggest the book "How to Lie with Statistics" by Darrell Huff. My local library has a copy, and it is an excellent read. You would be surprised how easy it is to mislead people by carefully selecting which data to show and how to show it.
... and remember, "87.3% of statistics are made up."
One "Red Flag" to me is when data is given in Percentages (%)!! Sounds better when 66% of the people polled want steak for dinner. Thats the 2 kids want steak and mom don't care (2 out of 3). ALWAYS find out what the n=(total number).