Scientology Logic 21
Logic 21 - Mathematics are methods of postulating or resolving real or abstract data in any universe and integrating by symbolization of data, postulates and resolutions.
Mathematics is a very broad subject and it is important to understand from the outset that it is not just arithmetic and algebra. There is an excellent description of mathematics on Wikipedia. That article begins with "Mathematics is commonly defined as the study of patterns of structure, change, and space." Math (American abbreviation) or Maths (rest of the English speaking world abbreviation) has been used not only to figure out your taxes but also to figure out complex physical universe laws (such as relativity). Once you have an understanding of the wide field of Math, you will see that Logic 21 is a pretty good definition of the subject that successfully covers all its aspects.
It's also important to realize that mathematics is more logic than counting. An example is working out the tip to pay your waiter. Even if you use a calculator there is a sequence with decisions (both elements of logic) in which you do things: 1. take the sales tax from the total cost, 2. get the actual cost of the food, 3. if the service was exceptional then multiply by 20%, 4. if the service was average then multiply by 15%, 5. if the service was less than average then multiply by 10%, 6. if the service sucked then multiply by 0%.
In order to generalize this formula to take into account fluctuations in tipping amounts we could create this formula:
t = f * s
where t is the tip amount, f is the cost of the food and s is the value of the service,
s = v - q
where s is the value of the service, v is the highest service value (in our example 20%) and q is a factor depending on the quality of the service (in our example, average service would have a q value of -5%, terrible service would have a value of -20%)
f = b - e
where f is the cost of the food, b is the total on the bill and e is the extras such as sales tax or other fees not related to the cost of food.
Now we have a general formula for calculating the amount of the tip and if you compare what we did to Logic 21 you will see that many of the elements of the logic were used to do this.