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

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1. Help Your Child or Teen Learn 
2. Solving Linear Equations
3. Fractions Ratios Rates Proportions & Units
4. Euclidean Geometry
5. Analytic Geometry/Functions 
6. Number Theory
7. More Calculus
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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.

Remainder Arithmetic for Real Numbers

Remainder or modulo arithmetic is useful in understanding polar coordinates, modulo 2p or 360 degrees,  and the periodicity of unit-circle trig functions and the complex-valued cis(q) = cos(q) + i sin(q) = exp(iq) function.

For any pair of real numbers d > 0 and n > 0, there is a natural numbers q > 0 and a real number r such that 

0 < r < d    and    n = qd +r  

Here the quotient q = the number of whole times that the divisor d goes into the dividend n, and r = the remainder. 

Here q and r may be computed via long division exactly or in principle via an infinite sequence of decimal approximations - their decimal expansions.  The case where d is a decimal fraction may be somewhat different (less involved) than the case where d is given by an infinite decimal expansion. We will skip the details.

Two natural numbers n and m are said to be equivalent or equal modulo d, when there remainders on division by d are equal. In this case, we write

 n = m,  modulo d.

Equality modulo a whole number or divisor d is

  • reflexive, that is,  each number n = itself, modulo d, or equivalent n = n, modulo d, for each natural number n. 

  • symmetric, that is,   n = m  modulo d when and only when  m = n  modulo d, and

  • transitive, that is,  if  n = m  modulo d, and  m = t  modulo d then  n = t  modulo d.

A whole number n is divisible by the divisor d when and only when  n = qd for some whole number q. That is when and only when  n = 0, modulo d and when and only when n is a whole or natural number  multiple of the divisor d.  The number 0 is a multiple of all divisors d. Observe, if n > m then  n = m,  modulo d when and only when  n - m is a multiple of d while if n < m then  n = m,  modulo d when and only when  m -n is a multiple of d.

Remainder Calculations for real numbers are based on the following properties or theorems. 

Theorem:  Suppose m, n, u and v are real numbers. Suppose d > 0 is a real number.   If  m = n, modolo d and   u = v, modulo d  then (i) m + u  = n +v modulo d, and (ii)  mu= nv, modulo d. 

Proof:  First, m = n, modulo d,  implies  m = a d +r and n = b d +r for some real numbers a, b and a common real remainder r with 0 < r < d. Likewise, u = v, modulo d,  implies  u = A d + s and v = B d +s for some real numbers A, B and a common real remainder r with 0 < s < d. 

Arguments for (i):  Suppose (m+ u) > (n+v)  then 

(m+ u) - (n+v) 

= (ad +r + Ad+s) - (bd+r + Bd+s) 
=  (a+A)d + (r+s) - [(b+B)d + (r+s)]
= (a+A)d-(b+B)d 
= [(a+A)-(b+b)]d

is a multiple of d, and hence (i)  m + u  = n +v modulo d holds when (m+ u) > (n+v).  The case where (n+v) > (m+u) follows similarly.

Arguments for (ii):  Suppose m u > nv  then 

mu - nv

= (ad +r)(Ad+s) - (bd+r)(Bd+s) 
=  aAd2 + asd+ Ard+ rs - [bBd2 + bsd+ Brd+ rs]
= [{(aA)-(bB)}d + (as-bs)]d 

is a multiple of d, and hence (i)  m  u  = n v modulo d holds when m u > nv.  The case where nv > mu follows similarly.


Calculator Usage: For every divisor d > 0 and every number N, there is a unique integer q such that  qd < N < (q+1)d so that r = N-qd satisfies 0 < r < d.  With the aid of a calculator, if N is positive, the whole number part of the decimal representation of the computed value of  N/d gives q > 0. But if N is negative, the whole number part of the decimal representation of the computed value of  N/d gives q+1 < 0, and q is one less than the whole number part of N/d. 

 

www.whyslopes.com
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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