Appetizers and Lessons for Mathematics and Reason (www.whyslopes.com)
||Définition d'une variable || Algèbre || Arithmetique || Logique ||La raison basée sur les règles et modelés||

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1A. Pattern Based Reason 
1B. Math Curriculum Notes
2. Three Skills for Algebra
3. Why Slopes & More Math

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YOU are better than YOU think. Show yourself  how:  

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Read  logic chapters 1 to 5  in online volume Three Skills for Algebra  for greater skills & confidence in  work 
and study

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 Logic chapters 1 to 5  re- appear not in sequence, as is or longer,  in  Volume 1A,  Pattern Based Reason, Bon Appetite.

Logic Mastery
 Amazing, Amusing, Amorous,  Delicious, Delightful, Edifying, Strengthening Elixir. 
It eases work & learning difficulties Makes the hard easier. Opens eyes. Leads to greater precision.
in reading and
writing

Logic mastery makes the hard, easier. Logic mastery  leads to better, stronger and richer comprehension.  Logic mastery  improves reading and writing.  Logic mastery ease learning difficulties.  Logic mastery gives a headstart.  In sum, logic mastery  will develops critical thinking, improve reading and writing, and give a firmer base for work and studies at many levels. Good luck.


After logic  (a) continue reading Three Skills for Algebra, chapters 8 to 14  and do so alongside site area on solving liinear Equations ; or (b) see this calculus starter lesson and Volume 3, Why Slopes  & More Math, chapters 2 to 6;

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Caution: Site advice is approximately correct, for some circumstances, not all. That leaves room for thought

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What may be learnt and when depends on how skills and concepts are developed. Making the hard easier and clearer will allow earlier & richer development of skills and concepts.


Try the Twiddla Whiteboard. In principle, it  allows to people to draw and chat together online on a copy of this webpage or a clean sheet. The chat may be via text or audio.  Visit www.twiddla.com to set up whiteboards to work with the webpage of your choice.

For online automated help in senior high school maths & calculus, visit  quickmath.com  For Automatic Calculus and Algebra Help with derivatives, integrals, graphs, linear equations, matrix algebra, visit calc101.com  With  overlap, each site quickmath & calc101offers a different range of services, some free, some not, all based on webmathematica. Good luck.

A Possible Start

Students need to know how to count. A knowledge of how counting might of began with tally marks on tally sticks (or walls) may provide a context. 

The Start of Number Theory Continues with the following pages

Adding Wholes
Multipling Wholes Distributive Law Preamble
Distributive Law for Wholes
Consequences More Consequences
What is a Fraction
Compound Fractions

after this one (and not the next links in top and bottom margins

Tally marks on a stick may have given the earliest way for an individual to keep track of how many objects possessed or owed.

One to One Correspondence between tallys and a set of objects

As long as there is a one-to-one pairing, matching or correspondence between the tally marks and the objects being tracked, the owner assumes none have been lost or gained. The tally marks altogether describe and visually count or keep track of how many objects there are. 

For example, a shepherd may put a tally mark on the tally stick above for each sheep that enters a pen, and later on verify as the sheep leave the pen that there is still one mark per sheep. That keeps track of the sheep and ensures none have been lost nor gain.  Births and predators are assumed to account for all changes in the correspondence. If the tally marks are all alike as they are made, the order in which sheep leave the pen may be different from then one the entered. All that is important in concluding that no sheep has been gains or lost is that each sheep on exit be in one to one correspondence with a tally mark and that all tally marks are used.

In pure mathematics, two sets are said to be have the same cardinality (count) or to be equipollent when and only when there is a bijection or one-toone-correspondence between them.  A bijection in brief is a one to one pairing between the elements of one set and the elements of the other, so all elements in each set belong along to one and only one ordered pair.  Tracking sheep or marbles with tally marks on a stick (or paper) provides a bijection between the set of tally marks and the set of sheep.

The shepherd in keep track of his sheep may have tally marks on several sticks. In that case, the sheep may be allowed to exit the pen via several exits. Again as long this exiting gives a one to one pairing between the sheep and tally marks, the shepherd and we assume none have been lost.  The sheep could be tallied in the first instant by entering the pen via several entrances or in several groups.  It is possible to allow the sheep to enter grouped in one way and to leave grouped in another way.  And if we tallied the entering and leaving each day using different tally ticks, and different groupings of the sheep and tally sticks,  the different tallies and the sheep should be in one to one correspondence.

Working Definition of Whole Numbers:  A set of tally marks on a stick gives a whole numbers. So whenever we speak of a whole number, we think of a set of distinct tally marks on a real or imagined stick.

Assumption

Tallying or Enumeration Assumption: If a set is tallied (counted) in two different ways, with or without the use of grouping, the set of tally marks for one way will lie in a bijection (one to one correspondence) with the marks in the other way. 

In other words, we assume any two ways to count the elements of a set will result in the same number.   Later on, we will see that the equality of two ways to count or measure what is a set or region leads to properties of arithmetic.

First Tallying or Enumeration Assumption:  For a person who can count,  the number of tally marks will be the same regardless of the order in which the elements of a set are tallied or counted. 

Remark for Students of Pure Mathematics:  The following gives a set theoretic justification of the unique tallying or enumeration principle

Two sets are equipotent when and only when there is a one-to-one  map from one onto the the other.   The latter notion works for both finite and infinite sets as well.  

Theorem:  If there is a  one-to-one map f of a set U into a proper subset W of itself then the set is not finite: 

Proof   If U  has N elements and we can find a one-to-one labeling of those N elements u of U given by a map  c(j): [1,N] -> U.  Now d(j) = f(c(j)): [1,N] -> W, a proper subset of U. Therefore, there is an element s in U not W. Pick such an s and Put  d(N+1) = s.  Then the extended map  d: [1,N+1] -> U  has a range with N+1 elements in U. The foregoing shows that if we count N distinct elements in U with the aid of the mapping c then with the aid of the  mapping  f, we can also count N+1 elements as well using another function d.  Therefore for all whole numbers N,  there is no bijective map of a range of whole numbers 1 to N onto U. That is what we mean by saying the set U is finite.  

Contrapostive form of theorem:  If U is a finite set (that is, is in bijective correspondence with a set of whole numbers 1 to N)  then then any one-to-one map of U into itself must be surjective.   - if it was not then U would be not finite, that is infinite.

Unique Tallying Theorem: If  P is a finite set with  two maps c: [1,N] --> U and d:[1,M] --> U are bijections of two possibly different intervals [1,N] and [1,M] then N = M. 

Proof: If N < M then for each j in the interval [1,M],  there is a unique u = d(j) in P and hence a unique  k = c-1(u) =  c-1( d(j) ) = f(j) in [1, N] and hence in [1,M]  Therefore f:[1,M] --> [1,M] is an injection. Yet [1,M] is finite. So the injection must be surjective and hence N = M.   The alternative possibility M < N is treated similarly. Q.E.D.

Note each of the maps in the Unique Tallying theorem represents a way to count the number of elements in the set P 

 

Collecting the tally marks into groups provided a counting or numeration.  Today, we go further. In decimal notation we use digits 1 to 9 to as marks for single object or a group of them, and we use place value to keep track of how ones, tens, hundreds, thousands etc there are in a count.  So we track groups of power of ten instead of individual elements of a set or sheep in a pen. None the less, tallying goes on. And when we are counting elements of a set, we assume the final count or the decimal for it will be independent of how and in which order the set elements are tallied, counted or numbered.

Decimals

Decimal notation provides a compact form of tally marks for tallying or counting or describing how many objects there are in a set. The decimal view of numbers and number theory may be read parallel to the general number theory pages.


The Start of Number Theory Continues with the following pages

Adding Wholes
Multipling Wholes Distributive Law Preamble
Distributive Law for Wholes
Consequences More Consequences
What is a Fraction
Compound Fractions

after this one (and not the next links in top and bottom margins

 

 

 

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Number Theory

Start of Number Theory

Origins of Counting or Tallying
Adding Wholes
Multipling Wholes
Distributive Law  Preamble
Distributive Law for Wholes
Consequences
More Consequences
What is a Fraction
Compound Fractions

Number Theory
Continued


Decimal Place Value
Comparison Method
Addition Method
Subtraction Methods
Multiplication Methods
Division Methods
Remainder Arithmetic I
Primes & Composites
Primes Factorization
Primes & Composites
Prime Factorization Aids
Prime Factorization Examples
Counting  Whole No.  Factors
Arithmetic Videos
Square Roots
Fractions & Decimals
Fractions as Decimals
1 = 0.999 Recurring
Long Division Continued
Ratio of Simple Fractions
Ratio of Decimal Fractions
Unsigned Reals Numbers
Signed Coordinates
Plane Vectors
Horizontal Vectors
How to Add Reals
How to Multiply Reals
Distributive Law for Reals
Remainder Arithmetic II

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