Transcript Family Fun with Math

Presented By Tracy Flinchbaugh and Lisa Marsteller
South Eastern School District
Ideas for transitions modified from
http://www.swsd.k12.pa.us/baresvle/MathMaterials/alternat_algor.htm
Partial Sums
An Addition Algorithm
Partial Sums
Add the hundreds (600 + 400)
Add the tens (50 +80)
Add the ones (8 + 7)
Add the partial sums
(1000 + 130 + 15)
658
+ 487
1000
130
+ 15
1145
You try it!
Add the hundreds (500 + 800)
Add the tens (70 +40)
Add the ones (2 + 3)
Add the partial sums
(1300 + 110 + 5)
572
+ 843
1300
110
+
5
1415
A Subtraction Algorithm
10
0
12
- 5
5
7
2
5
5
7
8
Starting with the ones column, ask
yourself, can I do 2 minus 7? No, so the
2 goes next door and borrows a ten.
We change the 1 to a 0, and our 2 in
the ones column becomes 12.
Next, go to the tens column, and ask
yourself, can I subtract 5 from 0? No, so the 0
goes next door and borrows a hundred. The
8 becomes a 7, and the 0 becomes a 10.
Now subtract right to left.
1
2
11
1
15
- 2
9
9
6
2
6
You try it!
8
9
Starting with the ones column, ask
yourself, can I do 5 minus 9? No, so the
5 goes next door and borrows a ten.
We change the 2 to a 1, and our 5 in the
ones column becomes 15.
Next, go to the tens column, and ask yourself,
can I subtract 9 from 1? No, so the 1 goes
next door and borrows a hundred. The 9
becomes an 8, and the 1 becomes an 11.
Now subtract right to left.
2
5
Lattice
Multiplication
A Multiplication Algorithm
Lattice Multiplication
5
6
1
To solve 56 * 43, write the
problem around the grid.
Multiply each of the
numbers around the grid
writing one number on
each side of the diagonal
line.
Add each diagonal
column, regrouping
(carrying) when
necessary.
Rewrite the answer with
the problem.
2
2
2
0
1
4
1
5
4
0
56 * 43 = 2,408
8
4
3
8
5 * 4 = 20
6 * 4 = 24
5 * 3 = 15
6 * 3 = 18
You try it!
To solve 41 * 38, write the
problem around the grid.
Multiply each of the
numbers around the grid
writing one number on
each side of the diagonal
line.
Add each diagonal
column, regrouping
(carrying) when
necessary.
Rewrite the answer with
the problem.
4
1
1
1
0
2
3
3
0
2
5
5
41 * 38 = 1,558
8
3
8
8
4 * 3 = 12
1*3=3
4 * 8 = 32
1*8=8
A Multiplication Algorithm
Break down 86 into 80 + 6 and
52 into 50 + 2.
Multiply each part of the first
number by each part of the
second number.
Multiply 80 * 50
Multiply 80 * 2
Multiply 6 * 50
Multiply 6 * 2
Add the partial products
86
* 52
4,000
160
300
+ 12
4,472
You try it!
Multiply 30 * 20
Multiply 30 * 7
Multiply 1 * 20
Multiply 1 * 7
Add the partial products
31
* 27
600
210
20
+ 7
837
Partial
Quotients
A Division Algorithm
The Partial Quotients Algorithm uses basic facts and
extended facts that students know. There are multiple ways
of getting to the correct answer.
Ask yourself about how many
6’s are in 158. Are there at
least 10? Yes, because 10 [6’s]
are 60.
Are there 20? Yes, because 20
[6’s] are 120.
Record 20 to the right and
subtract 120 from 158.
Ask yourself how many 6’s are in
38. Is there at least 1? 2? 3? 4?
5? 6? Yes, because 6 [6’s] are 36.
Record 6 to the right and
subtract 36 from 38.
6 158
- 120
38
Subtract - 36
2
20
Subtract
Can I take anymore 6’s out? No, so
I’m finished.
Add the numbers on the right, and
record the answer with the remainder.
+
6
26 R2
You try it!
Ask yourself about how many 12’s are in
6,481. Are there at least 100? 200? 300?
Yes, because 300 [12’s] are 3,600.
Record 300 to the right and subtract
3,600 from 6,481.
About how many 12’s are in 2,881?
Are there at least 100? 200? Yes,
because 200 [12’s] are 2,400. Record
200 to the right and subtract 2,400
from 2,881.
About how many 12’s are in 481? Is
there at least 10? 20? 30? 40? Yes,
because 40 [12’s] are 480. Record 40
to the right and subtract 480 from 481.
Can I take anymore 12’s out? No,
so I’m finished.
Add the numbers on the right, and
record the answer with the
remainder.
12
6,481
- 3,600
2,881
- 2,400
481
- 480
1
300
200
+
40
540 R1
Math websites
www.studyisland.com (PSSA math and reading practice)
http://everydaymath.uchicago.edu (supports EDM math
curriculum)
www.mathisfun.com (timed math facts practice, illustrated
math dictionary)
http://matti.usu.edu/nlvm/nav/vlibrary.html (great graphics,
manipulatives, and enrichment activities)
www.aaamath.com (explanation of math skills, interactive
practice, challenge games)
www.mathfactcafe.com (basic facts practice using
flashcards, printable worksheets for time and money)
http://www.mathleague.com/ (challenging mathematics and
math contests for 4th grade and up)
http://www.coolmath4kids.com/ (an amusement park of math)
http://arcytech.org/java/ (tutorial for specific math skills - great
graphics)
Top-It (addition, subtraction, multiplication,
and division)
 Multiplication Baseball
 Multiplication Wrestling
 War Games (addition, subtraction,
multiplication)
 Subtraction Target Practice
http://everydaymath.uchicago.edu

MATH TIPS
FOR
PARENTS
Ideas modified from
http://athomewithmath.terc.edu/math_kits.html
Number of the day…




Find one way to make the “Number of the day”.
38 + 27 – 24 = 41
1 quarter, 1 dime, 1 nickel and 1 penny is $0.41
Find more ways to make the number
100 - (3 x 25) + 16 = 41
82 x 0.5 = 41
Take time to find 11 in your day.
The time is 41 minutes after 9:00.
How long does it take to drive 41 miles?
If someone is born in 1941, how old would they be?
Food for thought…


How many pizzas do we need for our party?
How many guests will we have?
How many slices per person?
How many batches of cookies will we need to
bake for friends and family?
How many people?
How many cookies per person?
How many cookies in a batch?
Ingredients and amount needed?
How much longer?



Talk through the problem.
“Are we there yet?”
“How long until we eat?”
Figure out how much longer.
Round to a time that’s easier to work with
and then adjust, such as round 5:18 to 5:20.
Explain solutions.
How much do we save?




Talk about grocery coupons and store savings.
Cut out coupons with your child.
Make grocery list for the week.
Predict cost and savings.
Use a calculator as you shop or estimate in
your head.
Have your child pay the cashier and count the
change.
Find out the savings.
Check totals on receipt and compare with
predictions.
Wish list…




How much would you get to spend?
$20? $50? $100? $300? $1,000?
What would you buy?
Browse catalogs, internet, or go window
shopping.
Have your child make a wish list.
Estimate the cost, tax, shipping, and
totals.
Discuss everyone’s choices.
Comparison shopping…did you make the
best buys?
What would you have done differently?