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Estimating
and Rounding
Measures of
Central
Tendency
One Step
Equations
Metric System
Heuristics
$100 $100 $100 $100 $100
$200 $200 $200 $200 $200
$300 $300 $300 $300 $300
$400 $400 $400 $400 $400
$500 $500 $500 $500 $500
Estimating and Rounding for $100
Round to the tenths
place:
71.349
Answer
71.349 => Tenths place
71.349 => The four rounds down
71.3
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Estimating and Rounding for $200
Estimate by rounding to the
ones place:
11.49 – 5.15
Answer
11.49 – 5.15 => 11 – 5 = 6
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Estimating and Rounding for $300
Estimate using front end
estimation:
9.327 + 5.72 + 4.132 = ?
Answer
9.327 + 5.72 + 4.132 = ?
9.327
5.72
+ 4.132
18 1.1
18 + 1.1 = 19.1
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Estimating and Rounding for $400
Estimate using clustering:
21.2 + 20.7 + 22.1 + 20.3 + 21.1
Answer
21.2 + 20.7 + 22.1 + 20.3 + 21.1
Each one is close to 21 so,
21 * 5 = 105
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Estimating and Rounding for $500
Estimate 40.364 / 7.811
using compatible numbers
Answer
40.364 / 7.811
40 / 8 because these are
compatible numbers (they
divide evenly)
40/8 = 5
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Measures of Central Tendency
for $100
Find the range:
9, 23, 5, 57, 9, 3
Answer
Range is
largest # - smallest #,
So 57 – 3 = 54
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Measures of Central Tendency
for $200
Find the mode:
Cam, tao, dau, cam, dau,
xoai, xoai, thom, tao,
cam, xoai, chom chom
Answer
There are 2 modes:
Cam and xoai each
occur three times
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Measures of Central Tendency
for $300
Find the median:
10, 23, 17, 20, 21, 5, 14, 10
Answer
10, 23, 17, 20, 21, 5, 14, 10
Re-order the numbers from least to
greatest:
5, 10, 10, 14, 17, 20, 21, 23
There are 2 middle numbers: 14
and 17. The mean of these 2
numbers is 31/2 = 15.5
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Measures of Central Tendency
for $400
Which measure of central
tendency best describes the
following situation?
Height of buildings in district 1
Answer
Median
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Measures of Central Tendency
for $500
Find the mean and the
outlier(s) (if any). Describe
how the outlier(s) effect
the mean:
120, 97, 113, 110, 24, 107
Answer
120, 97, 113, 110, 24, 107
Mean:
(119+97+113+110+24+107)/6 = 95
Outlier: 24 => it is much smaller than the
rest of the numbers
Mean Without Outlier:
(119+97+113+110+107)/5 = 109.2
The outlier decreases the mean by 14.2
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One Step Equations for $100
Find the perimeter of a rectangle
if the length is 8cm and the
width is 3cm
Answer
Perimeter of a rectangle = 2(l+w)
Length = 8cm; Width = 3cm
P = 2(l+w) = 2(8cm+3cm) = 2(11cm)
= 22cm
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One Step Equations $200
Solve for x:
-5.2 + x = 7.1
Answer
-5.2 + x = 7.1
-5.2 + 5.2 + x = 7.1 + 5.2
x = 12.3
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One Step Equations for $300
The formula for the
surface area of a
2
sphere is SA = 4(pi)r
If the radius is 2m, what
is the surface area?
Answer
2
4(pi)r
SA =
r = 2m
2
SA = 4(3.14)*2 = 4*3.14*4
2
= 16 * 3.14 = 50.24m
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One Step Equations for $400
Solve for x:
x/(-5) = 8
Answer
x/(-5) = 8
x/(-5) * (-5) = 8 * (-5)
X = -40
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One Step Equations for $500
Write and solve an
equation for the following
situation:
Madison bought 12
mangos and spent 93,000
Dong. How much did she
spend on each mango?
Answer
Let x equal the price of each
mango. Then, 12x = 93,000D
So, x = 7750D
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The Metric System for $100
10 grams = 1 ______
Answer
10 grams = 1 dekagram
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The Metric System for $200
27.92 milliliters = ____ liters
Answer
27.92 milliliters = 0.02792 liters
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The Metric System for $300
2.84 hectometers = ____ millimeters
Answer
2.84 hectometers = 284,000 millimeters
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The Metric System for $400
What is the appropriate unit
of measure to estimate the
capacity of a sink?
Answer
Liters
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The Metric System for $500
Estimate the height of the
classroom using
appropriate units. (must be
close)
Answer
Actual Height: 2.79 meters
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Heuristics for $100
Chloe stacks some blocks as shown. If
she continues the pattern to 10 rows,
what is the total number of blocks she
will use in the 10th figure? The figure
below is the 5th figure in the pattern.
Answer
nd
2
First row is 1 block,
is 2
rd
blocks, 3 is 3 blocks and
so on. So, 10 rows would be
10+9+8+7+6+5+4+3+2+1 =
55 blocks
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Heuristics for $200
Beginning at 6:50 A.M.,
planes leave an airport for
New York every 45 minutes.
You arrive at the airport at
10:15 A.M. How long will you
have to wait for the next
plane to New York?
Answer
6:50 + 45 = 7:35 + 45 =
8:20 + 45 = 9:05 + 45 =
9:50 + 45 = 10:35
10:35 – 10:15 = 20 minutes
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Heuristics for $300
The houses on your street are
numbered with odd numbers
starting with 1 and ending with
201. How many house numbers
contain at least one 7?
Answer
From 1 – 100, the odd numbers
with at least one 7 are:
7, 17, 27, 37, 47, 57, 67, 71, 73,
75, 77, 79, 87, 97
There are 14 numbers. So in
200 there would be 14*2 = 28
numbers
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Heuristics for $400
A dime is 1.25 mm thick.
How many meters high
would a stack of dimes
worth $50 be?
Answer
There are 10 dimes in a dollar, so
$50 * 10 dimes/dollar = 500 dimes
500 dimes * 1.25mm/dime = 625mm
1000mm = 1 m so,
625/1000 = 0.625m
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Heuristics for $500
A school band has a brass section of
trumpet, trombone, and tuba players.
There are twice as many trombones
as tubas, and half as many
trombones as trumpets. If there are
two tubas in the band, what is the
total number of players in the brass
section?
Answer
Let x be the number of tubas, then
x=2
Number of trombones = 2x = 4
Number of trumpets = 2*2x = 4x =8
2+4+8 = 14 total players
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