Number Operations & Proportional Reasoning K-8 Teachers
The text discusses various methods for teaching subtraction and addition, emphasizing different algorithms and properties. Subtraction is described with examples such as "take away"
Day2: 11/18 - Percentages -
is : =
of: x (multiplication sign)
what : n, x (variables)
change % to decimal
EX: 72% β 0.72
10 % off
this means that for every $100, you get 10% off
1/10 = 0.1 = 10%
21/100 = 0.21 =21%
* Equivalent Fractions for Conversions *
2/5 = 40/100 = 0.41 = 41%
* Divide to Convert *
1/8 = 1 Γ· 8 = 0.125 = 13%
0.125 = terminating decimal
5/6 = 5 Γ· 6 = 0.833333 (repeating decimal)
= 83%
Ο (pi) = 3.14... (irrational number)
pi is just like love, irrational and never ending
Practice:
8 is what % of 22
8 = % x 22
22a = 8
22/22 a = 8/22
a= .36666 = 37%
Day 1: 11/16 - Decimals -
3 7 5 .
β β β
β β ones
β tens
hundreds
one-to- ten relationship
β # get bigger (10 times)
β # gets smaller (10 times)
whole/ 1 unit = 100 single cubes
(imagine a whole as a ten by ten row unit)
10x 10s = 1 unit
1 x10 = 1/10 (part of a unit)
1 x 1 = 1/100
Day 1: 11/16 - Decimals -
3 7 5 . 2 5 3 (# after decimal=parts of a unit)
β β β
β β thousandths
β hundredths
tenths
3 7 5 . 2 5
β β β β β
β β β β β
β β β β 1Β’
β β β 10Β’
β β $1
β $10
$100
β x 10 Γ· 10 β
What does a decimal do?
It separates the parts from the whole
# in between decimals
0.3 & 0.4 β 0.35
0.32 & 0.33 β 0.321, 0.322...
Week 13
11/11: VETERANS DAY - NO SCHOOL
11/09: (absent) TEST OVERVIEW
Week 12
11/04: CLASS CANCELLED
11/02: TEST #2
Week 11
Day 2: 10/28 - HW & TEST Review/ Mind-map in Class
1. 1/3 cups of sugar needed to make 2 loaves
How many cups of sugar are needed for 3 loaves?
- 1/2 a cup of oil to make 3 loaves
2. Sometimes you have to simplify when adding fractions with a least common denominator
** Review for test
Day 1 : 10/26 - Fraction Problems in class -
1. 3/4 cups per serving
2 and 2/3 needs to prepare, how many cups of oil will she need?
2 cups
2. 3/4 pizza
1/2 ate
How much did he eat? He ate 3/8 of the pizza
3. if 4 * = 2/7 of the whole
** ** ** ** ** ** **
2**= 1/7
whole of 14 stars total
Week 10
Day 2: 10/21 - In Class Fraction Problems -
1. Jim, Ken, Len, and Max have a bag of miniature candy bars from
trick-or-treating together. Jim took ΒΌ of all the bars, and Ken and
Len each took 1/3 of all the bars. Max got the remaining 4 bars.
How many bars were in the bag originally? How many bars did
Jim, Ken, and Len each get?
Jim= 12
Ken and Len = 16 each
Max = 4
total: 48
2. Jim, Ken, Len, and Max have a bag of miniature candy bars from
trick-or-treating together. Jim took ΒΌ of the bars. Then Ken took
1/3 of the remaining bars. Next, Len took 1/3 of the remaining
bars, and Max took the remaining 8 bars. How many bars were in
the bag originally? How many bars did Jim, Ken, and Len each
get? How is this problem (with regards to fractions) different
from Problem 1?
Jim= 6
Ken= 6
Len= 4
Max= 8
3. 3/4 of a pie in refrigerator
John ate 2/3 left over
How much did he eat?
John ate 1/2 of the pie
4. Three-fourths of the class are girls. Two-thirds of the girls have black hair. What fraction of the class is female and dark-haired?
half of the class have dark hair
**Look back at notes
Day 1: 10/ 19 - Fractions Continued-
identity property of multiplication:
2/3 + 2/2 = 4/6
25/100 Γ· 25/25 = 1/4
** find common factor for both 25 and 100
a/a = 1 x/x= a
28ab2/42a2b2 =
7*4*a*b*b / 7*6*a*a*b*b
= 4/6a = 2/3a
Adding Fractions with common denominator
3/12 + 2/12 =5/12
1/4+3/4= 4/4 =1
Adding Fractions with different denominator
1/4 + 1/6
l l
v v
3/12 + 2/12 =6/12 = 1/2
- Find the least common multiple by finding the multiple
** Yard example (look back at notes)
Week 9
10/ 14 - FRACTIONS -
Fraction: is a part of a whole; it is a symbol that represents a part to a whole
- quotient
-part of a whole
- division
- ratio (to be a fraction - part to whole not part to part)
EX: 3/10 3= part 10 = whole
30 balloons
3 red
27 blue
3/30
27/30
How you can demonstrate fractions to students:
- surface area (region)
-shading
- length
- folding a paper
- number line
- line segment
Mistakes made by students:
1/2 < 1/8
2/3 + 1/5 = 3/8
Practice:
4/7 or 5/7
4/5 or 4/9
3/7 or 5/ 8
9/10 or 3/4
Wholes: 8/8, 6/6, 4/4, 3/3, 1/2
what did you discover? When you use all the pieces you have 1 whole numerator = denominator = 1 whole
10/11 NO SCHOOL
Week 8
Day 2: 10/07 - Prime Numbers -
Prime #s: 2,3 5, 7, 11,13,17,19,23, 29,31 37, 41,43,47,53,59
GCF: greatest common factor
LCM : least common multiple
List Method:
24: 1,2,3,4,6,8,12,24
36:1,2,3,4,6,9,18,36
GCF: 12
**you use common factors when you simplify
EX: 25/100 Γ· 5/5 = 5/20 Γ· 5/5 = 1/4
vs.
if you use your GCF 25/100 Γ· 25/25 = 1/4
24: 24, 48, 72, 96
36: 36,72
LCM: 72
**improper fraction 10/15 + 9/15 = 19/15
Prime Factorization :
20:1,2,4,5,10
20 20
/ \ / \
4 5 2 10
/\ /\
2 2 2 5
2 x 2 x 5 = 22 x 5
**If you take your found GCF and multiply by the remaining #s = LCM
EX:
24: 2 x 2 x 2 x 3
36: 2 x 2 x 3 x 3
GCF: 12
after doing prime tree:
24: (23 x 3)
36: (22 x 32)
12 x 2 x 3 = 72
** list method is preferred for students due to the fact that if they mess up trying to find the GCF/LCM they will mess up their GCF/ LCM (both numbers)**
Day 1: 10/05 - Divisibility and Factors -
Divisibility: βaβ is divisible by βbβ, if there is a number βcβ that meets the requirements
EX: 10 is divisible by 5
b x a = c
5 x 2 = 10
Important Terminology:
*10 is divisible by 5
or 5 divides 10
*5 is a divisor of 10
*5 is a factor of 10
*10 is. multiple of 5
Divisibility Rules:
βββββββββ-
Ending
By 2: 0,2,4,6,8
By 5: 0,5
By 10: 0
(a number is divisible by 2 if it ends in a 0,2,4,6,8; 5 is divisible if a number ends in 0,5; 10 is divisible by a number if it ends in 0)
Sum of Digits:
By 3: *when the sum of the digits are divisible by 3*
EX: 543 5+4+3 = 12/3 = 4
By 9: * when the sum of the digits are divisible by 9 ; just like #3*
Other:
by 6: if it is divisible by both 2&3
EX: 3702
Last Digits:
by 4: if the last two digits are divisible by 4
EX: 3,728 28/4
by 8: if the last three digits are divisible by 8
Special Numbers:
by 7:
EX: 826
step 1 - (double last digit) 6x2=12
step 2 - (take your first two digits from your given number and and subtract it from step 1) 82-12 = 70
*70 is divisible by *
*if there is a bigger number repeat the first two steps*
Chop-Off:
by 11:
-Chop off last two digit numbers
- add them to the remaining number(s)
- repeat
EX: 29,194
291 +94 = 385 ; 85+3 = 88/11=8
Factors:
28: 1,2,4,7,14,28
42:1,2,3,6,7,14,21,42
39: 1,3,13,39
91: 1,7,21,91
84: 1,2,3,4,6,7,12,14,21,28,42,84
60: 1,2,3,4,5,6,10,12,15,20,30,60
\ /
composite numbers
Prime numbers: *have two factors* when it has factors of 1 and itself
Prime #s 1-60: 2,3,5,7,11,13,17,19,23,29,31,37,41,43,47,53,59,61,67,71,73,79,83,89,97
0: not a prime - not composite
1: not prime- not composite
0: additive identity element
1: multiplicative identity element
Week 6
Day 2: 9/23 - Algorithms vs. Strategies
Algorithm - when you have pencils and paper
Strategies - things we do in our brain when we don't have a pencil and paper by us
- Mental Strategies -
Addition:
1. Left to Right (Front-end Addition)
347 + 129
Head: 300 + 100 = 400
40+20 = 60
7+9 = 16
--------------------------
= 476
2. Compensation
67+29
Head: 67+30 = 97
-1
---------------------
96
3. Compatible numbers
130 + 50 +70 +20+ 50
Head: 50+50 + 70 + 130 + 20
l l l l
l l
100 200
= 320
4. Breaking Up & Bridging
67 + 36
Head: 67 + 36
l l
_l_
l l
30 6
67 + 30 = 97
+6
----------------
103
Subtraction:
1. L -> R
a) 47-32 = 15
Head: 40-30 = 10
7-2 = 5
-----------------
= 15
2. Breaking up and Bridging
67 - 36 = 31
Head: 67 - 36
l l
l
l l
30 6
67 - 30 = 37
-6
----------------
32
3. Compensation
47 - 29 = 18
Head: 47-30 = 17
+1
ββββββββββ-----
18
4. Compatible Numbers:
170 - 50 - 30 - 50 =
Head:
170+ 30 = 140
50+50 = 100
140-100= 40
Multiplication:
1. Compatible numbers
2 x 9 x 5 x 20 x 5
Head:
5 x 2 = 10
20 x 5 = 100
9 x 1000
= 9,000
2. L -> R
3x 123
Head:
3x(100+20+3)
300+60+9 = 369
Division:
1. Compatible Numbers
105 Γ· 3
Head:
150 Γ· 3 =
l__l
_l__
l l
90 +15
90/3 = 30
> 35
15/3 = 5
TEST REVIEW***
Day 1: 9/21
Class Cencelled
Week 7
09/30 *TEST OVERVIEW*
09/28 *TEST 1*
Week 5
Day 2 (9/16) - Division
4 r 4
5/ 24
- 20
---------
4
4 = quotient
4 = aka 4/5
5 = divisor
24 = dividend
*division symbol* = vinculum
11 Γ· 3 = 3 r 2
11-3 = 8
8-3 = 5
5-3 = r 2
Standard Algorithm
158 r 1
3 / 475
- 3ββ
---------
17 β
- 15 β
----------
25
- 24
----------
01
Standard Alg. Emphasis on Place Value
158 r 1
3 / 475
- 300
---------
175
- 150
----------
25
- 24
----------
01
**separation of the numbers into three boxes***
Alternate Algorithm
197 cookies
βYou work at a factory and your boss tells you to put 13 cookies in bagsβ
12 r 5
16 / 197
- 160 10 bags
---------- + 2 bags
37 ------------
- 32 12 bags
----------
5
https://www.youtube.com/watch?v=KGMf314LUc0
Day 1 (9/14) - Multiplication
Grouping
3 groups of 2
β 3x 2
β 2+2+2
β 2, 4, 6
4 groups of 3
β 4x3
β 3+3+3+3
β3,6,9,12
**number line example **
**Clock example**
**array 3 x 8 ***
Commutative Property of Multiplication
3 x 8 = 8 x 3
Identity Property of Multiplication
a x 1 = 1
Zero Property Of Multiplication
a x 0 = 0
Associative Property of Multiplication
(a x b ) x c = a x (b x c)
Distributive Property of Multiplication
3 x (5 + 2) = (3 x 5 ) + (3 x 2)
β β
partial product
β When you multiply a number by a sum, the product remains the same
Multiplication Algorithms
1. Standard Algorithm of Multiplication
β regular way of multiplying in the U.S
2. Place Value
23 4x 3 = 12
x 14 4 x 20 = 80
-------- 10 x 3 = 30
322 10 x 20 = 200
3. Expanded Notation of Multiplication
23 = 20 + 3
x 14 = 10 + 4
-------- ----------
90 + 2
200 + 30 + 0
(+100)
----------------------
300 + 20 + 2
4. Lattice Algorithm of Multiplication
β Lattice box
β apply the numbers around the box
β solve the problem within the box
https://www.youtube.com/watch?v=FJ5qLWP3Fqo
Week 4
Day 2 (9/9) - Subtraction
Subtraction
- known as "take away", "missing addend" ,
- "I have four cookies, how many more do I need to get from the cookie jar so I have a total of 7?"
4 + πͺ = 7
-4 -4
---------------
πͺ = 3
- "I have 4 cookies, Skyler has 3 cookies, how many more cookies do I have?"
34 β minuend
- 12 β subtrahend
-------
22 β difference
1. American Standard Algorithm
- Subtract as you were taught (USA)
2. European- Mexican Algorithm
- subtract (R to L)
- borrow from the bottom row numbers but make those a digit bigger
3. Reverse Indian
- Subtract (L to R)
- borrow from the numbers you have acquired from your answer
4. Left to Right
- focuses on place value
- like the Reverse Indian but you demonstrate the actual place values vs just numbers
5. Expanded Notation
https://www.youtube.com/watch?v=ShCq1BVVbQ0
Day 1 (9/7) - Addition
Properties of addition:
1. Identity Property of Addition
a + 0 = a
2. Commutative Property of Addition
a + b = b + a
3. Associative Property of Addition
(a+b) +c = a + (b+c)
Addition :
1. Standard American Algorithm
576
+ 279
----------
- Start from the one's place (R to L)
- 6+ 9 =15
- write the 5 in the ones;add the 1 up of the 7
2. Partial Sums Algorithm
- (R to L)
-add starting at the ones
- when the total of the row equals more than the place value, take it down to the total vs putting it above the next place value
3. Partial Sums - Emphasis on Place Value
-(R to L)
- add starting at the ones
- when adding, place the total below the equal sign but put the actual total instead of putting it above the next place value
4. Left to Right Algorithm
-(L to R)
- add in an expanded form kind of way
5. Expanded Notation
- (R to L)
- add in expanded notation terms
- Place value explicit
6. Lattice Algorithm
- (R to L)
- draw a lattice box and add
https://www.youtube.com/watch?v=kTBZdIXizDQ
Day 1 (8/31)- intro to Base 10, 5, 3
-Base 10-
Digits used: 0,1,2,3,4,5,6,7,8,9
numeral system: base- 10 system
expanded notation = powers of ten
5, 375.32
5 - thousands
,
3 - hundreds
7- tens
5 - ones
.
3 - tenths
2- hundredths
$275.25
2 - hundred dollar bills
7- ten dollar bills
5 - ones dollar bills
.
2 - dimes
5- pennies
Expanded Notation: 273
200+70+3
= (2x100) + (7x10) + (3x1)
-Base 5 -
Digits Used: 0, 1, 2, 3, 4
43β = 23
(4 x 5) + (3x1)
(4 x 5^1) + (3 x 5^0)
20 + 3 = 23
11.1β =
=(1 x 5) + (1x1) + (1x 1/5)
=(1x 5^1) + (1x 5^0) + (1x 1/5)
5 +1+ 1/5 = 6 1/5
- Base 3 -
Digits Used: 0, 1, 2
111β = 13
(1 x 9) + (1 x 3) + (1 x 1)
=(1 x 3^2) + (1 x 3^1) + (1 x 3^0)
9 + 3+ 1 = 13
211β =
(2 x 3^2) + (1x 3^1) + (1 x 3^0)
=(2x9) + (1x3) + (1)
= 18 +3 +1
= 22
https://www.youtube.com/watch?v=jdfrwxUkXOk
Week 2
Day 2 (8/26) - Problem Solving
A student was making sandwiches
13 of the sandwiches had a slice of cheese.
14 had a slice of salami.
13 had a slice of tomato.
8 had a slice of cheese & a slice of tomato.
Only 3 had a just a slice of salami.
5 had a slice of tomato, a slice of cheese, & a slice of salami.
8 had a slice of tomato & a slice of salami.
How many sandwiches did the student make?
In our groups we attempted to figure out the best way to solve this problem. Then we shared how we came up with the answer. After sharing, the instructor demonstrated how to solve the problem with a ven diagram.
The total was : 21 sandwiches
Day 1(8/24) - Problem Solving
We were introduced to the use of sticks and cubes to problem solve. Students learn best in different and unique ways. When problem solving, we have to
1. understand the problem
2. devise a plan (strategize)
3. carry out the plan
4. reflect ( does it work?)
Problem Solving Strategies:
1. Look for a pattern
2. Examine a related Problem
3. Make a diagram
4. Work backwards
5. Use guess and Check
6. Write and equation
https://www.youtube.com/watch?v=J3GGx9wy07w
Week 1
Day 1 (8/19) - We went over the syllabus and Mind-map assignment
https://player.mediaamp.io/p/U8-EDC/qQivF4esrENw/embed/select/media/cO8kAp7DPj_c?form=html
Number Operations & Proportional Reasoning K-8 Teachers