Here are the steps:1) Let x = number of coins originally2) Gave 1/4 of x to sister = x/4 coins3) Remainder is 3/4x 4) Gave 1/2 of 3/4x to brother = 3/8x5) Marcus had left = 3/4x - 3/8x = 3/8x = 186) 3/8x = 187) 8x/3 = 188) 8x = 18 * 3 = 54 9) x = 54/810) x = 48Therefore, the original number of coins is 48
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Similaire à Here are the steps:1) Let x = number of coins originally2) Gave 1/4 of x to sister = x/4 coins3) Remainder is 3/4x 4) Gave 1/2 of 3/4x to brother = 3/8x5) Marcus had left = 3/4x - 3/8x = 3/8x = 186) 3/8x = 187) 8x/3 = 188) 8x = 18 * 3 = 54 9) x = 54/810) x = 48Therefore, the original number of coins is 48
NCTM 2010 Regional Conferences & Expositions Denver 2Jimmy Keng
Similaire à Here are the steps:1) Let x = number of coins originally2) Gave 1/4 of x to sister = x/4 coins3) Remainder is 3/4x 4) Gave 1/2 of 3/4x to brother = 3/8x5) Marcus had left = 3/4x - 3/8x = 3/8x = 186) 3/8x = 187) 8x/3 = 188) 8x = 18 * 3 = 54 9) x = 54/810) x = 48Therefore, the original number of coins is 48 (20)
Here are the steps:1) Let x = number of coins originally2) Gave 1/4 of x to sister = x/4 coins3) Remainder is 3/4x 4) Gave 1/2 of 3/4x to brother = 3/8x5) Marcus had left = 3/4x - 3/8x = 3/8x = 186) 3/8x = 187) 8x/3 = 188) 8x = 18 * 3 = 54 9) x = 54/810) x = 48Therefore, the original number of coins is 48
1. Professional Development
Singapore Mathematics
Seoul 9 – 11 July 2012
Dr Yeap Ban Har
yeapbanhar@gmail.com
Marshall Cavendish Institute Singapore
Presentation slides are available at
www.banhar.blogspot.com
MAP101
www.mcinstitute.com.sg
www.facebook.com/MCISingapore
2. FUNDAMENTALS
of singapore
math
Mayflower Primary School, Singapore
Slides are available at
www.banhar.blogspot.com
3. Introduction
This course is an overview of Singapore
Math. It includes the what and how of
teaching mathematics.
16. 110 g
180 g 110 g
Bella puts 180 g brown sugar on the dish.
290 g
17. on an identical dish
110 g
2 units = 180 g
1 unit = 90 g
180 g 110 g
3 units = 270 g
Bella puts 270 g brown sugar on the dish.
290 g
18.
19. Singapore Math is based on the CPA Apporach.
Pictorial representations can be more concrete
(pictures) or more abstract (diagrams such as bar
model).
An alternate way to solve the brown sugar
problem:
20. Singapore Mathematics
focuses on the ability to
visualize. For example,
bar models are used
extensively.
Bar models were introduced to overcome the
pervasive problems students had with word problems
– even the basic ones.
21. Such word problems are used to help
students
Deal with information
Handle and clarify ambiguity – one
dish or two
Develop visualization – bar models
are used extensively
Practice mental strategies – numbers
used are not difficult to compute
23. Procedural & Conceptual
Understanding
Singapore Math places an emphasis on
both. Procedures are explained in a
conceptual way. For example, long
division is seen simply as breaking
large numbers into smaller ones before
dividing.
24.
25.
26.
27.
28.
29.
30. Using number
bonds to make
sense of long
division
Differentiated Instruction for advanced
Over-
learners – how does one get the result
emphasizing
of 51 3 from 60 3.
procedural Balancing
knowledge procedural
knowledge
with
conceptual
understanding
51. Method 1
The positions of 11, 22, 33 are at C, H, E respectively.
Positions of multiples of 11 can be located.
Method 4
The position
for 99 can be
found by
writing out all
the numbers
Method 3 but this is not
Numbers ending with 9 efficient
are at E. So, 99 is at E method.
Method 2 too.
The positions of numbers ending with 1 and 6 can
be located ta either ends. Thus 91 or 96 can be
located. Subsequently, 99 can be located.
54. Method 1
The letters under A and I are
even. So 99 cannot be there.
Method 2
The positions of numbers ending
with 9 form a diagonal pattern.
Method 3
The numbers under first D
increases by 8. Thus 17 + 80 = 97
is under first D. The position for
99 can be worked out.
Method 4
The positions of multiples of 8 I is
definitely under A. 8 x 12 = 96 is
under A. The position of 99 can
be worked out.
Method 5
Numbers under V is 1 less than
multiples of 4. So, 2011 (1 less
than 2012) is under V. 99 is less
than 100.
55. Method 2
The positions of numbers ending with 9
form a diagonal pattern.
The methods were the ones that
participants in Chile came up with.
56. Another Method
In a course done in December 2010 with a group of
Chilean teachers, there was a method that involves
division. For Cheryl, it was 99 10.
For David, it was 99 8. Are you able to figure out that
method?
69. Multiplication Facts
We do a case study on multiplication
facts. We will see the use of an anchor
task to engage students for an
extended period of time.
70.
71.
72.
73.
74. Strategy 1
Get 3 x 4 from 2 x 4
Strategy 2
Doubling
Strategy 3
Get 7 x 4 from 2 x 4 and 5 x 4
Strategy 4
Get 9 x 4 from 10 x 4
85. … and, later, diagrams. Students also
write multiplication sentences in
conventional symbols.
86. First, equal groups –
three groups of four. Third, four multiplied three
times ….
Second, array –
Three rows of four
87. Textbook Study
Observe how equal group
representation evolves into array and
area models. Also observe how the
multiplication tables of 3 and 6 are
related on the flights of stairs.
98. Students who were already good in the skill of multiplying two-digit number
with a single-digit number were asked to make observations. They were
asked “What do you notice? Are there some digits that cannot be used ta
all?”
105. FUNDAMENTALS
of singapore
math The following slides are for additional
tasks that are discussed on the second
day for Grades 5 – 8
Mayflower Primary School, Singapore
Slides are available at
www.banhar.blogspot.com
106.
107.
108.
109.
110.
111.
112.
113.
114. Marcus gave ¼ of his coin collection to his sister
and ½ of the remainder to his brother.
As a result, Marcus had 18 coins.
Find the number of coins in his collection at first.
3 units = 18
8 units = ???
Marcus had 48 coins at first.