# Marina Ho

## Wednesday, January 8, 2014

## Saturday, September 14, 2013

### I Teach K: EDU330 Elementary Mathematics 08/17/13 Session 6

I Teach K: EDU330 Elementary Mathematics 08/17/13 Session 6: Today, you had fun with Ms Peggy Foo on lesson study and solving a bunch of enrichment lessons as well as to learn about differentiated inst...

## Sunday, August 18, 2013

### Gelman's Counting Principle

__Gelman’s Counting Principle__
How do we know
whether children can count ?

If knowing how to
count just means reciting

the numbers (i.e.,
‘‘one, two, three...”) up to “five” or

“ten,” perhaps
pointing to one object with each numeral,

then many
two-year-olds count very well.

Of course, counting
only tells you number of things if you do it correctly,

following the three
‘how-to-count’ principles identified by Gelman and

Gallistel (1978). These are :

enumerating a set,
one and only one [numeral] must

be assigned to each
item in the set.”

counting must be used in the same order in any one

count as in any other count.” and

(3) The cardinal principle, which
says that ‘‘the [numeral] applied to the

final item in the set represents the
number of items in the set.”

As Gelman and Gallistel pointed
out, so long as the

child’s counting obeys these
three principles, the numeral

list (‘‘one,” ‘‘two,”
‘‘three,”... etc.) represents the cardinalities

1, 2, 3,... etc.

However, observations
have shown that three-year-old

children often
violate the one-to-one principle by skipping

or double-counting
items, or by using the same numeral

twice in a count.

Children also violate
the stable-order principle, by producing different

numeral lists at different
times.

The cardinal principle can also be
viewed as something more profound

– a principle stating that a numeral’s cardinal meaning is determined by

its ordinal position

in the list. This means, for example, that the
fifth numeral in

any count list – spoken or
written, in any language – must

mean five. And the third numeral
must mean three..

If so, then knowing the cardinal
principle means having

some implicit knowledge of the
successor function – some

understanding that the
cardinality for each numeral is generated by

adding one to the cardinality for
the previous numeral.

Thus Gelman feels that
preschoolers learn to count as a result of the

perfecting of counting
procedures.

Do you agree ?

Marina Ho-BSc08

## Saturday, August 17, 2013

### Fast Math Tricks - How to multiply 2 digit numbers up to 100 - the fast ...

The multiplication method my teachers never taught me. I wish I had learnt this way earlier. I was taught the top down method.

## Friday, August 16, 2013

__Pick’s Theorem__
This
formula was created by Georg Alexander
Pick in 1899.

Using
the Geoboard to Assist :

·
Draw a polygon on the Geoboard

·
Determine the number of boundary points
and the number of interior points and calculate its area

·
Repeat with different polygons

·
Draw polygons without any interior
points and find the area

·
Draw polygons with one interior point
and find the area

·
Draw polygons with two interior points
and find the area

·
Prepare a table with number of boundary
points, number of interior points, and area. Discover that the relationship
between B the number of boundary points, i the number of internal points, and
the area of the geoboard polygon is given by Pick's formula

**A = I + ½ B – 1**

**The diagram below explains this further.**

I understand this better now! Wow :)

Marina Ho

BSc08

## Wednesday, August 14, 2013

### Elementary Math - Day 3 Blog

**What is Subitizing ?**

**Perceptual subitizing**

Perceptual subitizing is closest to the original
definition of subitizing: recognizing a number without counting. For example,
children might "see 3" without using any learned mathematical knowledge.

**Conceptual subitizing**

But how is it that people see an eight-dot domino
and 'just know" the total number? This is Conceptual subitizing. They are
able to see the relationship between numbers when dealing with different
quantities. These people are capable of viewing number and number patterns as
units of units (Steffe and Cobb 1988).

Spatial patterns, such as those on dominoes, are one
kind.

**Subitizing and counting**

Young children may use perceptual subitizing to
make units for counting and to build their initial ideas of cardinality.

By : Marina Ho - BSc08

Seed Institute

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