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Welcome to module 2.
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Making sense of multiplication and division.
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This is lesson one multiplicative comparison.
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The learning goals for this lesson.
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At the end of this lesson he will be able
to demonstrate and explain understanding of the difference between multiplicative ...
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and additive comparison.
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Understand the math structures or situations product unknown, group size
unknown, number of groups unknown to determine the operation.
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Solve both unknown factor and unknown product multiplicative comparisons with
the model and equation using the symbol for the unknown.
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This is part one.
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Additive comparison and multiplicative comparison.
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In this partthe learning goal is to demonstrate and explain
understanding of the difference between multiplicative and additive comparison.
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Additive comparison.
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This compares two amounts by telling how much more or
less something is compared to the other.
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In this situation Kayla is 6 years old
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and Mike is 12 years old.
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When we compare their amounts were going to tell
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how many
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more years older Mike is or less Kayla is.
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In this case Mike is 6 years older than Kayla.
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That is additive comparison.
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Multiplicative comparison.
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Compares two amounts by telling how many times greater or
less one is in comparison to the other.
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We're looking at the same situation Kayla 6 years old
Mike is 12 years old.
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But in this case we are saying Mike is twice
as old as Kayla.
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We are using multiplication
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to show the comparison.
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Let's look at some situations for both.
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It takes Mark 5 minutes to walk home.
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from school.
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It takes James 10 more minutes than Mark
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to reach his home.
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How many minutes does it take James to arrive home?
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In this case
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James time is equal to Mark plus 10 minutes.
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James time is equal to 5 minutes which is Mark's
time plus 10 minutes. Therefore James time is 15 minutes ...
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to walk home.
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This here is an example of additive comparison.
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Let's look at this again, it takes Mark 5 minutes
to walk home from school it takes James three times ...
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that amount
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to walk home from school.
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How many minutes does it take James to arrive home?
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In this case we're looking at James time is equal
to 3 times Mark's time.
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James time is equal to 3 times 5 minutes because
5 minutes was how much time it took Mark to ...
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walk home.
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So James time is a total of 15 minutes to
walk home.
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This is an example of multiplicative comparison.
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Here's another situation.
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Dan and Kenny were playing basketball. Dan scored 18 points.
Kenny scored 12 points less than Dan.
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We want to know how many points did Kenny score?
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If we look here Dan is equal to 18 points;
we're given that information Kenny is equal to Dan take ...
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away 12 points.
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Because Dan has more points.
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Kenny is equal to 18 - 12.
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So we know that Kenny's points, he scored 6 points.
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This is also an
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Example of additive comparison.
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Same situation.
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Just a little bit different
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Dan and Kenny were playing basketball. Dan scored 18 points.
Dan scored three times as many points as Kenny.
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How many points did Kenny score?
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So Dan we know that he had 18 points.
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Dan is three times the amount of points Kenny scored.
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So 18 we substitute in
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is equal to 3 times Kenny so we can use
18 divided by 3.
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will give us Kenny's score.
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Kenny scored six points. This is an example of multiplicative
comparison.
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Now it's your turn to determine if a situation is
additive comparison or multiplicative comparison.
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Complete the check for understanding 4 part 1.