We have just finished chapter 5 in which we dealt with equations, multi step equations, and several wrinkles of inequalities. We'll now start chapter 6 and our first lesson will cover operations with ratios.
Chapters:
00:00 Introduction
03:33 How to write a ration in simplest form
06:59 Ratios involving measurement
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0:00
so we're going to talk about ratios
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right so we finished chapter five so and
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now we're going to talk about ratios and
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the question is why do we need ratios we
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need it because they're used to do what
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they're used to compare quantities so by
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definition a ratio is a comparison of
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two quantities by division all right so
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this is why we use ratio yes a lot of
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times when um they're saying what ratios
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are in real life it's a lot of like
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baking and stuff yeah well
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ratio you use it in like a lot of B you
0:33
say baking is that what you said yeah
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baking yeah right so you can use them in
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baking you can use them in a lot of
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things right for example if I wanted to
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know the ratio of boys to girls in this
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classroom what would it be said 9 9 to
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four about N9 I think it's uh no we have
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we it's 14 of you guys right so it's 10
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to
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four so 9 and four all right so it's 9
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and four we don't have everybody here so
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yeah is not here not here right so if I
1:03
was to find that ratio it would be 94
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and if I was say the ratio of boys to
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girls be 4 to n so there's three ways to
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write a ratio right you can have the two
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dot dot five that's one way to write it
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2 to five or 2 to five like this 2 to
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five okay or simply you can just write
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it as a fraction 2 over five so there
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like three main ways to write a ratio
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okay 2 do do 5 2 to 5 or 2 to five yeah
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um so the first number would always
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beator yeah the first number is always a
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numerator good observation right A to B
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if his letters a to b or A over B right
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so if I say for example what's the ratio
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of um pencils to pains in your book bag
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oh Z to zero Z
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0 to Z that's you know that 0 to0 is
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does not exist it's called in
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determination you have
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that1
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01
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what you have you can't have 0.1 pencils
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that's
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impossible one all right so what about
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the ratios of the ratio of
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um sneakers to dress
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shoes zero to zero what about o boots to
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sneakers
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all
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right I Boots the isue of those who love
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mine from those who hate
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m is that
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so wow all right only so just because I
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think I'm going to give her extra credit
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then because she's the only one I love
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you can't do
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that do that why do you mean I can I'm
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enti to do that I can make that decision
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I can take that fortive she's crazy I'm
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I'm win my right to do
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iter I
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don't but I don't
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like okay so now the first thing we want
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to do is we're going to learn how to
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write ratios in their simplest form
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right we've already done stuff like this
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in the previous chapters we've learned
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how to to do what how to simplify
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fraction so it's not going to be nothing
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new the only things that change here is
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that we call them ratios but it is the
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same thing right for example Express the
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ratio 12 baskets in 18 attempts as a
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fraction in its simplest form explain
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its meaning so how would you do that how
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would you solve this problem let's say
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you went and play your basketball game
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and you shot 18 times and you only made
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12 shots right so how would you explain
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Express that ratio yeah 12 12 18 right
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be 12 gabri I can hear your voice
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here 12 to8 right now they saying that
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Express Express this as a fraction so we
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want this in fractional form so how
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would it be then it be 12 over what 18
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12 over 18 and then I want us to
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simplify that right simplify we're not
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going to leave it like this we're going
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to simplify yes
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divided by what three three all right
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that's a good that's a good way to start
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three so we get four over 6 can we go
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any further yes yes what two two right
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two so we get what 2/3 two over3 so how
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how would you explain this if I want you
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to explain this ratio what does that
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mean in terms of a basketball player
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since you guys you play basketball Caleb
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so two to three so how would you explain
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it two or three made percent how would
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you explain that made out of three two
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two shot made out of what three is that
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a good percentage or that yes it's
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pretty good right I want that guy on my
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team two he makes two shots out of three
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I want him on my team right
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yeah I have you sit on the bench for a
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little bit until you
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get right so two to three so that means
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it makes two baskets out of three shot
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attempt all right so this is how you
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explain this now next example 10 out of
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30 Americans own MP3 player
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right so what does that mean so how
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would you express this ratio as a
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fraction in it simplest
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form and explain its meaning 10 out of
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uh 30 yeah you WR 10 do 30 right what
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that's 10 do3 or now we want it as a
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ratio as a fraction we want it as a
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fraction so how you 10 over 30 and then
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what does that give you simplify divide
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by 10 divide it by 10 right got one
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three what does that
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mean huh what does that mean explain it
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every one out of three
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people one people own the MP3 player
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right do you know what the MP3 player is
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right
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oh MP3 player you remember those uh like
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iPods or something yeah the iPod at the
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time iPad were like MP3 player back back
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then it was big thing right when they
6:35
came out and then the iPhone came and
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then blew all of that out of the
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building right so that's
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a yeah
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so so now the next thing we going to
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learn how to do which is a little bit
6:49
now complicated is what she mentioned
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right we talk about we use this kind of
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stuff in baking now I'm going to talk
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about ratios involving measurement right
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measurement
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you cry anybody right example we want to
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try to express the ratio of 8 O to 3 lb
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as a fraction in its simplest form so
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how would you do this one here 8 oz to 3
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lb 8 8 over three all right that's a
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good start right 8 over three but can we
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do
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this what do we have we have what ounces
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and we have pounds so what is the what
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is the issue here what is the problem
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here different me there two different
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things right so since if you're cooking
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right and you have this so how would you
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try to hurt yourself so you know exactly
7:41
what the ratio is measure out8 o and
7:44
then measure out three measure so we
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have to turn there's two options we have
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to turn pounds into what ounces so one p
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is equal to how many
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ounces we know that one pound who knows
7:58
the ratio what what's the one is how
8:00
many ounces the equivalent of what 1
8:02
pound 16 so 16 * 3 we have to memorize
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16 I give it to you so one pound is the
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equivalent of how many ounces who knows
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16 16 16 o you guys know better than I
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do bro I didn't know
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that right so one pound is equal to 16
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oz right but how many pounds do we have
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3 lb so why don't we just convert the 8
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oz to half a pound we can do that too
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there's two options right we can do that
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too we got to turn the 3 lb into O So 3B
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equal to how many
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o 3 lb will be what be 3 * what 3 * 16 o
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which is
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basically 48 oz right now we can find
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this ratio because both of these uh
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units both of these um quantities have
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the same unit now we have 8 O over 48 O
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So now that's going to be
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8 over 48 and because they are both
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ounces right so now we can do the ounces
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and then the ounces are going to cancel
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out so now we divide by eight be one
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over six so that ratio becomes one 2 six
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right this is probably one of the
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easiest chapters in the book pretty much
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right so now what I want you to do is I
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want you to go to your textbook if you
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have it and we're going to work on 1
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through 15 we have plenty of time yet on
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page um 26 6
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267 page
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266 267 this is a pretty easy
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section it's
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F your fun is very much
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