# Math and Arithmetic

## Math is the study of abstractions. Math allows us to isolate one or a few features such as the number, shape or direction of some kind of object. Then we can study what can be learned about the behavior of those features while ignoring everything else about the object.

###### Asked in Math and Arithmetic, Brain Teasers and Logic Puzzles, Algebra

### There is a bus with 7 children inside. Each child has 7 bags. Inside each bag there are 7 big cats. Each big cat has 7 small cats. All cats have 4 legs each. How many legs are on the bus?

As a riddle, the answer is zero legs on the bus since
the bus has wheels instead of legs.
But as a maths problem; It's not a tricked
question -- just a straightforward maths problem
Confirmed answer is 10990 legs.
§ Let's say the whole situation simply :
- There are 7 girls.
- Each girl has 7 backpack
- Each backpack has 7 big cats
- Each big cat has 7 little small cats.
§ Question: How many legs are there in the
bus?
§ Let's focus on each part of the question systematically,
write down on a piece of paper if you have to, following my steps
of chains.
1. Focus on the first girl first:
A B C D E F G
Girl A has 7 backpacks
2. Now focus on first backpack A1 :
A1 A2 A3 A4 A5 A6 A7
Backpack A1 has 7 big cats
3. Now focus on first big cat :
1 2 3 4 5 6 7
? Each big cats have 7 small cats (that's the
end of the focus)
Systematically, 7 small cats has 28 legs (7 *
4) combined with the big cat that owns this 7 small
cats.
Let's call this the "cat chain", so cat chain 1
has 32 legs altogether.
? So since there are 7 big cats
7 * 32 = 224 legs
? Therefore each backpack has 224 legs
? Finally, each girl has 7 * 224 = 1568
legs.
Lastly, since there are 7 girls, A to G, there are 7 * 1568
legs (per girl) = 10976 legs.
Now, since each girl also has 2 legs each;
SO, (7 * 2) + 10976 = 10990 legs altogether
Note: Disregarding bus driver, buses and etc…Only focus on the
girl and their backpacks!
Or
There are 7*7 = 49 bags and there are 7 + 7*7 = 56 cats in each
bag, meaning there are 56*4 = 224 legs in each bag. So including
the 7 children that have 2 legs each, there are 7*2 + 49(224) =
10990 legs in total.

###### Asked in Scattergories and Words Starting with Certain Letters, Math and Arithmetic

### What are some math words that begin with the letter J?

A list of math terms beginning with J appears below:
Jacobi Polynomials
Jacobian (A Determinant)
Jefferson Factor
Jensen's inequality
Jet
Jeton (not related to Jet)
Join (sum of sets)
Joint Probability
Joint Variation
Jordan Canonical Form
Jordan Matrix
Jump Discontinuity
Junctions
Justification
j (used in electronics to represent the square root of -1)
Juxtaposition
junction Justify

###### Asked in Math and Arithmetic, Algebra, Area

### How much tonnage air conditioner is required for 2779 sq ft?

It depends a great deal on where you live and how well your home
is insulated. Square feet is not a great help when planning the
size of an air conditioner. It is very useful to also have the
cubic feet in the home, along with the sizes and types of
windows.
Where I live in the northwest US, a 3-ton unit would do the
trick easily, but then, we do not get the intensely hot, long
summers as you might in say, Phoenix.

###### Asked in Math and Arithmetic, Chemistry, Statistics, Percentages, Fractions, and Decimal Values

### What is the percent error formula?

Percent Error is the difference between the true value and the
estimate divided by the true value and the result is multiplied by
100 to make it a percentage. The percent error obviously can be
positive or negative; however, some prefer taking the absolute
value of the difference.
The formula is the absolute value of the experimental value
(minus) the theoretical value divided by theoretical value times
100.
% error = (|Your Result - Accepted Value| / Accepted Value) x
100