2. Addition of Counts - Combining Tallies
Addition of tallies A and B
With the use of tally sticks, numbers are represented by marks on
the tally sticks. Decimal notation provide a shorthand way of
representing those marks on paper or some other writing material.
Saying how to perform an operation defines it. This page defines
addition.
A physical conception of the sum of tallies A and B follow via the
joining of tally ticks end to end when numbers A and B are represented by
tally marks.
In the foregoing addition is first introduced using tally marks.
The correspondence between decimal shorthand notation for numbers and
tally marks is (I hope) obvious. Addition can be introduced with
tally marks and then represented on paper using decimal place value
notation to represent numbers instead of using tally marks to represent
the same numbers.
Tallying, Counting and Enumeration Assumption
Second Tallying or Enumeration Assumption: If a group A
has N elements and a group B has M elements with M and N finite and
with both groups have no elements in common, then the number of
elements P in the union A+B of the two sets A and B is finite and
depends only on M and N. The number P is called the sum of M and N.
In terms of tally marks: A tally stick with M marks put end-to-end with
a stick with N marks yields a whole number P.
To answer the question what is the sum of two numbers M and N, find
two disjoint sets A and B with M objects and N objects in them. Marks on
a tally stick will do. Then the union A + B is a set with say P
objects. To count the number of elements in A + B, we may
count the elements of A first and then count the elements of B second to
get a number which we denote M+N, or we may count those in B first and A
second to get a number which we denote by N+M. Due to the unique
counting assumption. Since the ordering of the objects in the union A+B
is not important to the count P of elements in it, we must have P =
N+M and P = M+N. So M+N = M+N.
The foregoing defines the sum of M and N since for any two whole numbers,
as the number N+M= M+N of elements in a disjoint union of two sets with M
and N sets respectively. The fact that M+N = N+M for whole numbers
is called the commutative law for addition.
Counting the Objects in Several Groups
Associative-Commutative Law for Addition of Tallies:
A+B+C+D+E = ( [ (A+B) + C] + D) + E =
(A+B) + ( [ C + D) + E ) = ....
Assumption: If we have several whole numbers A, B, C, D and
E (sets of marks on tally sticks) then their sum A+B+C+D+E can be
computed in any order, and the size of the resulting set of tally marks
is independent of the order. See picture for two different orders.
The associative-commutative law as described here is a consequence of the
assumption that the full set of tally marks represented by tally sticks A
to E can be counted in any order without affecting the result. But
each such order corresponds to an ordering and grouping of the terms in
the sum A+B+C+D+E. So the way in which the sum is computed does not
affect the result, namely the total number of tally marks.
Food for thought: Is necessary to rewrite the above ideas in a
clearer manner?
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Teachers & Tutors: Site pages offer better or best practices for providing skills -
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Others are welcome to refine or exceed it. Please do.
Secondary
Mathematics for Ages 11+, A Practical Approach for home-tutoring or -schooling, or for schools & colleges
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Road
Safety Messages and Questions: When and why should you face
traffic when walking along a road or cycle path? Is it a good
idea to hang limbs outside of cars etc? What gives more
protection in a crash: a car, motorbike or bicycle?
See too, the BBC-Belgium story Texting and
Driving - texting & the impossible test - the article links to a gruesome utube video on the subject
The Logic of Injustice:
How Texas sent
an innocent man to his death - The wrong Carlos. Some judgments are irreversible. Procescution: Where and when prosectors play to win rather than for
justice, guilt beyond a reasonable doubt goes unrespected due to prosecutors who putting winning
first, those innocence before the law may be convicted. Some procescutors offices in continuing to accuse after a pardon
due to reasonable doubt or innocent being shown, may sucessfully oppose compensaton for false convictions
by asserting a pardon individual is still under suspicion. Then the pardoned individual or the latter's estate
is not compensation for years or decade
of improper or false imprisonment, or for execution. Site chapters on Logic
and some in Pattern
Based Reason may slowly lead to greater precision in reading, applying and
writing laws.
May 2012, Composition Starting:
Pre-School and Primary Mathematics - Quantitative Skills, An
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Parent-friendly
Work Booklets for ages 3+ to 13 Use these or others to check
or build skills. Other booklets are available but these booklets
allow parents unsure of themselves in mathematics to help their
children. The selection acquired in Canada is published in the
USA. So it has a US orientation. In retrospect, the selection
shows parents what to check with the booklets or by other ways,
the choice is theirs. But in retrospect, the selection does not
cover integral and fractions liquid weights and measures - ask
the publishers to correct that! For ages 9 to 12 say, parents may
compensate by showing boys and girls how to use weights or mass,
and further measures in food preparation. Beyond that children
may be shown how to measure and calculate angles, lengths and
areas [proportional amounts too] directly or by using maps and
plans drawns to scale. Learning how to gather and measure all the
ingredients, pots and pans for a dish or a meal, along with
cleaning up sets the stage for like activities or experiments in
science courses, and in developing organizational skills,
gives boys and girls a head start. Good luck. At the other
extreme, more comprehensive than light, if your motto is
McCainian: drill, drill, drill then Toronto
mathematician and actor John Mighton's jump math organization has jump math
workbooks for at least grades 3 to 8 for at-home and in-school
use - training sessions for teachers available. Jump math has
been expanding to cover older students. Jump Math Samples: plus
Fractions for
Grades 3-4 & Grades 5-6 [Read] Free Resources grades 1 to 8
[unread - likely to be good]. and
Mathematics
Skills For Ages 3 to 14 - technical!
Skills with take
home value - A few ideas
Basic skills include
time-date-calendar Matters; money matters; map, plan and
scale diagram matters;counting, measuring and figuring;
decision making with logic and likelyhood; being careful and
being aware of the domino effect of mistakes; reading and
writing with precision.
Is your child able to add, subtract and multiply amounts
of money, work with fractions, work with clocks and calendars,
work with maps and plans, and measure length, weight-mass and
volume? Schools may promote your son or daughter without
providing basic skills in reading, writing and
arithmetic.
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Calculus Starter Lessons
Calculus Lessons Elsewhere:
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How to Ace Calculus: Street Wise Guide - Mostly
Text.
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Flash
Video for Calculus Phobics
They cover basic topics in ways likely to complement your
notes, your textbooks and site material. When Goldilocks
trespassed in the house of the three bears, she found three bowls
of porridge, two not to her liking, and one just right. Different
bears have different tastes. As invited guest here and elsewhere,
if one or more explanations is not to liking, try another. It may
be better or just right.
Unsolicited Advice
Learning to do and high marks if it comes to easy is often
deceptive - light rather than deep. For that reason, students
with learning difficulties determined not to let it get in their
way may go deeper and farther than those with none. High marks,
if the come easy, may be deceptive - provide a too light and not
a deep mastery. That could have been your problem in secondary
school, one that leads to comprehension shock or difficulties in
calculus and more generally in the first year of college. Bon
Appetite.
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