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Welcome back to another dothatmath session. Today we'll learn how to correctly perform the order of operations for evaluating math expressions. First we need to define what it is. The order of operations is a rule that teaches you how to evaluate an arithmetic expression in the correct order. PEMDAS (Parentheses, Exponents, Multiplication and Division (from left to right), Addition and Subtraction) can help us recall the order (from left to right). In this video, I will give you two examples and show you to work them out.
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good morning this is tahib and welcome
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back to another do the math video today
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we're going to talk about the order of
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operations now this is something that a
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lot of students struggle with and i
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wanted to just give you an example and
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show you how to work it out so basically
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first we need to always have our
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definitions what is the order of
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operation it's basically a rule that
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tells the correct sequence of steps for
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evaluating a math expression
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now a lot of time when people want to do
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this order of operations they use
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uh the acronym pemdas
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p
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e
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m
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d
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a s and what does that stand for
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p stands for parenthesis e for exponent
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m for multiplication
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d for division a for addition and s for
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subtraction basically
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multiplication um
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division parenthesis and exponent they
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take precedence over addition and
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subtraction so when you have a sequence
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of numbers and sequence of operation
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what you do is you always want to make
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sure you work on your parentheses first
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then your exponent then multiplication
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and division and usually the safest way
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to do it is to go from left to right so
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i'll give you an example on the board
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and i'm gonna work it out to show it to
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you okay so let's do that right now
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so basically what i wrote is
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3 minus 2 times 5
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divided by 2
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minus 6. notice that i didn't put any
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parenthesis so
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now there is no parenthesis and there is
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no exponent so what do we do so again
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we're going to look at this whole thing
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and we're going to go okay i need to
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identify my multiplication and my
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division so i have a multiplication here
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and i have a division here so what i'm
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going to do is i'm going to do my
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multiplication first and i'm going to do
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my division next and then when i'm done
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with it i'm going to go from left to
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right so it's always going from left to
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right and in this in this case because
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the multiplication comes before the
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division the safest way to do it is
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always to do the multiplication first in
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this case okay was because the
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multiplication and division they have
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the equal they have equal power but to
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be safe it's better to do the
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multiplication first so what i'm gonna
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do is this
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i'm gonna still write my three then i'm
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gonna do two times five that is ten you
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have to know your multiplication right
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and then ten
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divided by 2
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minus 6.
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now i'm getting somewhere now the next
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thing again remember your pemdas okay we
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go from left to right but multiplication
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and division always have precedence over
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any other operation so the next thing
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i'm going to do is i'm going to divide
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10 by 2 that gives me 5. so i keep my
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sign i have 3
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3 minus 5
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minus 6. now i'm going to go from left
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to right so 3 minus 5 is negative 2
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and i have negative 2 minus 6 that is
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negative 8. so this is how you do it now
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this is one way to do it now suppose you
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don't like this when you go i don't
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really like the way this looks i don't
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like having a sequence of numbers
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following one another i just want
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something more conventional so what i'll
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do is this i propose you do this
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so some people it's all about
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visuals okay some people like to look at
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things a different way so i can rewrite
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this and say this is equal to three
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minus two
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times five
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over two
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minus six now for some people this looks
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better because they go okay now see
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exactly what's going on so again it's
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the same process now i have three
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two times five is ten
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divided by two
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minus six
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so i have three
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minus five
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minus six this is negative two minus six
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which is negative eight
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the same thing we found before so it's
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the same process now you may want to do
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it the
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this way or you may just want to
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transform this into a simpler
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conventional operation and then work on
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it now let's give you an example another
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example i want to give you another
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example where we have exponent and we
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may have a parenthesis so let me write
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let me make up some real quick here
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give me about two seconds so let's say
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we have
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seven
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times
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two squared plus
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um
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seven plus three okay
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and then times
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five minus two
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all right and then divided by
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4
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times 2.
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so let's recall our rule okay we're
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going to recall our rule real quick
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so i have
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parentheses here i have exponent and i
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have multiplication and division so what
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do i do with this problem it is dense it
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looks beastly it looks like oh man i
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can't i don't know if i'm gonna be able
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to do this but we never panic when it
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comes to this don't panic that's the
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first thing don't worry about it so
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first we're gonna look for our exponent
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okay we have
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one exponent here and we have
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parenthesis here so i'm gonna do the
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parenthesis first so i'm gonna leave
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this alone
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so now i have my first parenthesis
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within a parenthesis so i'm going to do
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that so
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5 minus 2 that is 3
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divided by
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4 times 2 right now that i did it i have
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another parentheses i still need to
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finish it so i have now
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seven times two squared
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plus
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seven plus three times three that's nine
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so that's seven plus nine
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divided by four
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times 2
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okay i'm not done i still have a
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parenthesis here so that becomes 7
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times 2 squared
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plus 16
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divided by 4
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times 2 all right
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now
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i have a parenthesis here i can get rid
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of it i don't need it anymore i can get
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rid of it here we can just get rid of it
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so now we have his exponent here okay
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so i'm going to go from left to right
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i'm going to do my exponents so 7 times
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2 squared 2 squared is 7 times 4
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plus 16 divided by 4
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times 2. now for the sake of space
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i'm going to raise a little bit at the
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top here all right so we can have space
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and work on
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the top of the ball so i have this here
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so i have seven
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times four
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plus 16
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divided by four
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times two
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again
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what do i do from here
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again we have multiplication we have
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addition we have division and we have
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another multiplication so i'm gonna do
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my multiplication first here okay i'm
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gonna do that
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so i have seven times four that's 28
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plus
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i have
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16 divided by four now i have i have a
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division here and i have a
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multiplication now they have equal power
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but to be safe it's better to go from
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left to right so i'm going to do the
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division first because i'm going to go
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from left to right so 16 divided by 4
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that is 4
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times 2 and that gives me 28
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now 4 times 2 that is 8
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so it's 28 plus 8 which is 36. so you
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can see
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how we did this all right so again when
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it comes to the order of operation all
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you need to remember is you do your
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parentheses first then your exponent
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then your multiplication and your
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division and lastly your addition and
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your subtraction and the best way to do
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it is always to go from left to right to
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be safe
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hopefully this has helped you guys out
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if you have any questions do not
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hesitate to reach out to me the website
7:40
is do the math or do that math
7:46
dot com
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if you have any tutoring uh request you
7:51
can go on the website and i'll be glad
7:53
to help you i'll have a link for you
7:54
also in the video okay thanks for
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watching this is taipe and stay tuned
7:58
for more stuff thank you
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