the mean and the median - mcgraw hill education · math journal 2, p. 255 ... the mean and the...
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eToolkitePresentations Interactive Teacher’s
Lesson Guide
Algorithms Practice
EM FactsWorkshop Game™
AssessmentManagement
Family Letters
CurriculumFocal Points
Common Core State Standards
Lesson 10�6 835
Advance Preparation
Teacher’s Reference Manual, Grades 1– 3 pp. 124–126
Key Concepts and Skills• Order whole numbers.
[Number and Numeration Goal 6]
• Use data to complete a bar graph. [Data and Chance Goal 1]
• Find the median and mean of data sets. [Data and Chance Goal 2]
• Use graphs to ask and answer questions. [Data and Chance Goal 2]
Key ActivitiesChildren make bar graphs for given sets of data. They model the bar graphs with pennies and then rearrange the pennies to determine the mean (average) for each data set. They compare the mean and median of data sets.
Ongoing Assessment: Recognizing Student Achievement Use journal page 254. [Data and Chance Goal 1]
Ongoing Assessment: Informing Instruction See page 838.
Key Vocabularymean � average � median
MaterialsMath Journal 2, pp. 253 and 254Student Reference Book, pp. 80 and 83–85Home Link 10 �5 ruler or straightedge � tool-kit pennies or counters (30 per child) � stick-on notes (optional) � slate
Interpreting a Pictograph and Creating a Bar GraphMath Journal 2, pp. 255A and 255BStudent Reference Book, pp. 86–89Children use data from a pictograph to answer questions. Then they create a bar graph to show the same data.
Math Boxes 10�6Math Journal 2, p. 255Children practice and maintain skillsthrough Math Box problems.
Home Link 10�6Math Masters, p. 340Children practice and maintain skillsthrough Home Link activities.
READINESS
Graphing Dice RollsMath Masters, p. 339per partnership: 2 diceChildren make a bar graph to record dice-roll results.
ENRICHMENTMaking a Data SetMath Masters, pp. 341 and 342per partnership: countersChildren determine a set of data based on given landmarks and graph the data.
ELL SUPPORT Building a Math Word BankDifferentiation Handbook, p. 132Children add the term mean to their Math Word Banks.
Teaching the Lesson Ongoing Learning & Practice Differentiation Options
The Mean and the MedianObjectives To introduce the mean of a set of data; and to review the median of a set of data.t
�
835_EMCS_T_TLG_G3_U10_L06_576892.indd 835 10/5/11 10:49 AM
836 Unit 10 Measurement and Data
A Mean, or Average, Number of ChildrenLESSON
10 �6
Date Time
Activity 1 Make a bar graph of the data in the table.
The mean, or average, number of children in the six families in the table is 3 .
8
7
6
5
4
3
2
1
0
Num
ber o
f Chi
ldre
n
Kugel Abuka Lauer Miller Ellis BosnakFamilies
Activity 2(to be done later)
Use the table above. List the number of children in order.
112257
The median number of children in the six families in the table is
2 .
Family Sizes
Family Number of Children
Kugel 5
Abuka 1
Lauer 2
Miller 7
Ellis 1
Bosnak 2
240-266_EMCS_S_MJ2_G3_U10_576418.indd 253 2/28/11 2:33 PM
Math Journal 2, p. 253
Student Page
Getting Started
Math Message Make a bar graph of the data in the table on journal page 253.
Home Link 10�5 Follow-Up Have partners share answers.
6 × 9 = 54 7 × 8 = 56 9 × 4 = 36 3 × 90 = 270 70 × 7 = 490 80 × 6 = 480
60 × 70 = 4,200 80 × 80 = 6,400 40 × 90 = 3,600
Mental Math and ReflexesPose fact and fact extension problems like the following. Have children record the facts on slates and share their strategies for solving the fact extensions.
1 Teaching the Lesson
� Math Message Follow-Up WHOLE-CLASSDISCUSSION
(Math Journal 2, p. 253)
Check that children have completed the bar graph. Ask: What does the height of each bar represent? The number of children in that family
� Finding the Mean WHOLE-CLASS ACTIVITY
Number of Children(Math Journal 2, p. 253; Student Reference Book, pp. 83–85)
Ask whether anyone can remember how the class found an average class shoe length in an earlier unit. (In Lesson 3-1, 16 children lined up along a paper tape, each placing one foot heel-to-toe on the tape. After cutting off the leftover piece of tape, children folded the tape into 16 equal parts. Each part represented an average class shoe length.) Explain to the class that they are going to find the average number of children per family shown in the table using another method. Lead them in the following routine:
1. Cover each shaded cell in the bar graph with a penny (or other counter). What does each penny represent? A child
2. Level off the pennies; that is, rearrange the pennies so each column in the graph has the same number of pennies.
3. With a straightedge, draw a horizontal line just above the top row of pennies.
4. Remove the pennies.
PROBLEMEEEMMBLEBLEBLBLELLELLLLBLEBLEBLEBLEBLEBLEBLEBLEMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMEEEEEEEEEEEEEEEEEEEEEEEEPROBLEMSOLVING
LELELELLEMMMMMMMML MMMMMMMMMMMMMEEEEEEEEEEEGGGGGGGGGLLLLLLLLLVINVINVINVINVINVINVINVINVINVINVVINVINVINVINVVINVV GGGGGGGGGGNNVINVINVINVINVINVINVINVINVINVINVIVINGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGNNNNNNNNNNNNNNNNNNNNNNNNNGGGGGGGGGGGGGGGGGGGGGGGGSOLVING
ELL
NOTE Everyday Mathematics does not draw a distinction between bar graphs and histograms. For a discussion on how some people contrast them, see section 12.2.3, Organizing and Displaying Data in the Teacher’s Reference Manual.
Mathematical PracticesSMP1, SMP2, SMP4, SMP5, SMP6Content Standards3.OA.7, 3.NF.3b, 3.MD.3
836-839_EMCS_T_TLG_G3_U10_L06_576892.indd 836 3/12/12 11:54 AM
A Mean, or Average, Number of EggsLESSON
10 �6
Date Time
Activity 2(to be done later)
List the number of eggs in the clutches in order.
2468
10The median is 6 eggs per clutch.
10
9
8
7
6
5
4
3
2
1
0
Num
ber o
f Egg
s
a b c d eOstrich Clutches
Activity 1 Make a bar graph of the data in the table.
The mean, or average, number of eggs in thefive clutches is .6
�Ostrich Clutches
Clutch Number of Eggs
a 6
b 10
c 4
d 2
e 8
240-266_EMCS_S_MJ2_G3_U10_576418.indd 254 2/28/11 2:33 PM
Math Journal 2, p. 254
Student Page
Lesson 10�6 837
NOTE Although the mean for this set of data is a whole number, the mean for other data sets will likely be between two whole numbers. A more efficient way to find the mean will be introduced in Lesson 10-7.
Links to the Future
The horizontal line represents the mean, or average, of this set of data. In this example, the mean number of children per family is 3. To support English language learners, discuss the social and mathematical meanings of the words mean and average. Emphasize that in this mathematical context, mean and average describe the same thing.
Ask children to count the number of shaded cells above the line and the number of unshaded cells below the line.
● Are the number of cells the same? Yes. Each time a penny was moved, a shaded cell was matched with an unshaded cell.
● How could you find the place to draw the horizontal line without using pennies? By trial and error, draw a horizontal line so that the number of shaded squares above the line is the same as the number of unshaded squares below the line.
Another method of finding the mean is to model each family by drawing a medium-size circle for each family and putting in the required number of pennies or counters to represent the number of children. The counters are then redistributed among the families (without adding or subtracting any) so each family has the same number.
Have children read the essay on The Mean (Average) on pages 83–85 in the Student Reference Book.
� Finding the Mean of INDEPENDENTACTIVITY
Ostrich Egg Clutches(Math Journal 2, p. 254)
Children make bar graphs of the data set about ostrich egg clutches. They use one of the methods from the previous activity to find the mean number of eggs.
Ongoing Assessment: Journal Page 254 �
Recognizing Student AchievementUse journal page 254 to assess children’s ability to complete a bar graph. Children are making adequate progress if they successfully complete the bar graph. Some children may be able to find the mean number of eggs. [Data and Chance Goal 1]
The activities in this lesson are an early exposure to finding the mean of a set of data. Finding the mean of a data set is a Grade 5 Goal.
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Date Time
Interpreting a PictographLESSON
10 �6Big Bend National Park is located in southwestern Texas. It contains 801,163 acres of protected wilderness. About 350,000 people visit the park each year.
The pictograph below shows attendance at Big Bend National Park for one week in August. Use the data to answer the questions below.
Day 1
Day 2
Day 3
Day 4
Day 5
Day 6
Day 7
KEY: = 50 people
Visitors to Big Bend National Park
1. How many people visited the park on Day 4? 500 people
2. How many people visited the park on Day 2? 350 people
3. How many people visited the park on Day 5? 475 people
4. How many more people came to Big Bend National Park on Day 7 than Day 6?
175 more people
5. How many fewer people came on Day 1 than Day 3?
125 fewer people
240-266_EMCS_S_MJ2_G3_U10_576418.indd 255A 4/11/11 4:00 PM
Math Journal 2, p. 255A
Student Page
836-839_EMCS_T_TLG_G3_U10_L06_576892.indd 837 4/11/11 8:31 PM
838 Unit 10 Measurement and Data
Date Time
LESSON
10 �6 Making a Bar Graph from a Pictograph
255B
Use the information shown in the pictograph to make a bar graph. Remember to add labels and a title to your graph.
Day 1
Day 2
Day 3
Day 4
Day 5
Day 6
Day 7
KEY: = 50 people
Visitors to Big Bend National Park
Visitors to Big Bend National Park
Sample answer: Days of Visits1 765432
050
100150200250300350400450500550
Sam
ple
answ
er: N
umbe
r of V
isito
rs
240-266_EMCS_S_MJ2_G3_U10_576418.indd 255B 4/11/11 4:00 PM
Math Journal 2, p. 255B
Student Page
Date Time
Math BoxesLESSON
10 �6
3. James built a rectangular prism out of base-10 blocks. He used 30 cm cubes to make the base. He put 4 more layers of cubes on top of that. What is the volume of the prism he built?
150 cubic centimeters
2. There are 5 blocks in a bag. 2 blocks are red, 2 blocks are blue, and 1 block is green. What are the chances of pulling out a red block?
2 out of 5 chances
4. Complete.
1 gallon = 4 quarts
3 gallons = 12 quarts
1 pint = 2 cups
7 pints = 14 cups
1 liter = milliliters
5 liters = 5,000 milliliters
6. Color the circle so that it matches the description.
1 _ 2 blue
1 _ 3 green
1 _ 6 yellow
Which color would you expect the spinner to land on most often? blue
1. Measure each side of the triangle to the nearest centimeter.
cm4cm4
cm4
Perimeter = 12 cm 137–139
157–159
94
160 161
24 93
yellowblue
green
5. Molly is playing with 5 toy cars. This is only 1 _
3 of her set of cars. How many cars are in her complete set? Fill in the circlenext to the best answer.
A 5 _ 3 cars C 10 cars
B 5 cars D 15 cars
1,000
240-266_EMCS_S_MJ2_G3_U10_576418.indd 255 2/25/11 10:05 AM
Math Journal 2, p. 255
Student Page
� Finding the Median INDEPENDENTACTIVITY
of Sets of Data(Math Journal 2, pp. 253 and 254; Student Reference Book, p. 80)
Have children complete Activity 2 on journal pages 253 and 254. Children find the median number of children per family and the median number of eggs per clutch. If necessary, have them read page 80 in the Student Reference Book to review how to find the median, or middle value, of a set of data.
Ongoing Assessment: Informing InstructionWatch for children who have difficulty finding the median. They can write the number of eggs in each nest on a small slip of paper or a stick-on note. Have them put the numbers in order and then find the middle number(s).
2 Ongoing Learning & Practice
� Interpreting a Pictograph and PARTNER ACTIVITY
Creating a Bar Graph(Math Journal 2, pp. 255A and 255B; Student Reference Book, pp. 86–89)
Have children examine the pictograph on journal page 255A. Ask them to explain what each smiley face means. 50 people Next ask them to explain what one-half of a smiley face means. 25 people Have children work independently or with a partner to complete journal page 255A. When they have finished, children create a bar graph on journal page 255B to show the same data. Discuss the scale for the bar graph. Since the pictograph key shows that each smiley face represents 50 people, the scale for the bar graph could be in increments of 50.
� Math Boxes 10�6 INDEPENDENTACTIVITY
(Math Journal 2, p. 255)
Mixed Practice Math Boxes in this lesson are paired with Math Boxes in Lesson 10-8. The skill in Problem 6 previews Unit 11 content.
Writing/Reasoning Have children write an answer to the following: Choose one of the units of capacity in Problem 4. Describe the unit of capacity by using one of the personal
references for units of capacity from Lesson 10-5. For example, describe an object that has about the same measure as a liter (or the unit of capacity you chose). Sample answer: I have a water bottle that holds 1 liter of water.
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836-839_EMCS_T_TLG_G3_U10_L06_576892.indd 838 10/5/11 10:50 AM
� Home Link 10�6 INDEPENDENTACTIVITY
(Math Masters, p. 340)
Home Connection Children find the mean of a data set.
3 Differentiation Options
READINESS PARTNER ACTIVITY
� Graphing Dice Rolls 5–15 Min
(Math Masters, p. 339)
To provide experience with making a bar graph, have children predict how many times they think they will roll a 1 and then make a graph to record their results. When
children have completed their graphs, have them discuss their predictions and results.
ENRICHMENT PARTNER ACTIVITY
� Making a Data Set 15–30 Min
(Math Masters, pp. 341 and 342)
To apply children’s understanding of landmarks (maximum, minimum, range, mode, and median), have them use the given median, range, and mode to display a
possible data set when 5 children share 15 cookies. Children record their work on Math Masters, page 342 and make a bar graph of their data set on Math Masters, page 341.
ELL SUPPORT SMALL-GROUP ACTIVITY
� Building a Math Word Bank 5–15 Min
(Differentiation Handbook, p. 132)
To provide language support for landmarks, have children use the Math Word Bank template found on Differentiation Handbook, page 132. Ask children to write the term mean, draw a picture representing the term, and write other related words. See the Differentiation Handbook for more information.
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LESSON
10�6
Name Date Time
Making a Data Set
Alto
geth
er, 5
chi
ldre
n ha
ve 1
5 co
okie
s in
thei
r lun
ch b
ags.
� T
he m
edia
n nu
mbe
r of c
ooki
es is
2.
� T
he ra
nge
of th
e nu
mbe
r of c
ooki
es is
5.
� T
he m
ode
of th
e nu
mbe
r of c
ooki
es is
2.
How
man
y co
okie
s co
uld
each
chi
ld h
ave?
Use
cou
nter
s an
d th
e dr
awin
gs o
f lun
ch b
ags
belo
w to
org
aniz
e yo
ur d
ata.
Dra
w c
ooki
es in
the
lunc
h ba
gs to
mat
ch th
e de
scrip
tion
abov
e.
Gra
ph y
our r
esul
ts o
n M
ath
Mas
ters
, pag
e 34
1. R
emem
ber t
o in
clud
e la
bels
an
d a
title
.
Sam
ple
answ
er:
Lunc
h ba
g A
Lunc
h ba
g B
Lunc
h ba
g C
Lunc
h ba
g D
Lunc
h ba
g E
79– 81
319-359_EMCS_B_MM_G3_U10_576957.indd 342 2/28/11 2:17 PM
Math Masters, p. 342
Teaching Master
Lesson 10�6 839
Name Number of Goldfish
Reba 3
Bill 1
Lucy 7
Meg 0
Nate 5
Pat 2
Name Date Time
Mean, or Average, Number of FishHOME LINK
10�6
Many of us learned that to find the mean (average) of a set of numbers, we add all the numbers and then divide the total by how many numbers we added. In today’s lesson, the class tried a different method of finding the mean. After your child has completed the page, ask him or her to explain how this method works. In the next lesson, we will introduce finding the mean by adding the numbers and dividing to find the answer.
Please return this Home Link to school tomorrow.
Family Note
83–85
Reba Bill Lucy Meg Nate Pat0
1
2
3
4
5
6
7
Num
ber o
f Gol
dfis
h
Names
The table below listshow many goldfisheach child won atthe school fun fair.
1. Put a pennyover each shaded squarein the bar graph.
2. Move the penniesso that eachcolumn has the same number of pennies.
3. Draw a horizontal line across your graph to show the height of the pennies when all of the columns are the same height.
4. The mean (average) number of goldfish won by children at the fun fair is .3
319-359_EMCS_B_MM_G3_U10_576957.indd 340 2/28/11 2:17 PM
Math Masters, p. 340
Home Link Master
836-839_EMCS_T_TLG_G3_U10_L06_576892.indd 839 3/9/11 8:12 AM