How will you explain the following
1.) 14 - 8
2.) What is my change, if I had $14 and I bought a sandwich for $8?
3.) What is my change, if I had $14 and I bought two CDs, each $4 each?
4.) If I had $14 and I bought 2 blank CDs and received $6 change, what is the price of a CD?
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oooooo......... this is a nice question....... but I have kinda a straight odd answer for it.......... a variable is represented by a letter, which means it is a number that does not have a particular value, except when it is put as equals to something, eg. x= 2 + 3, then you can find the value of the variable x, but otherwise, it is an unknown number........ at least that is what I have in my head......:-P
ReplyDeleteAhhhh.....yesss.....daz a good one...same thing i think...a variable cud be anything letter of the alpha that take place of a particular number....and that letter cud be any number....it varied...hence the name.....a variable...:P...well at least daz wat i think...:P
ReplyDeletesimply put. a variable is a symbol (either a letter or character) used to represent a number (quantity). the symbol can represent any quantity......wel that's my thoughts
ReplyDeletewell all that correct to my thinking but is there a deeper meaning to any of this??? and the 14 - 8 that answer is 6 comparing to my knowledge, but that means you have 14 of something eg. apples and someone else take 8 away from you, so now you count what you remain with and you will get 6, but that is the simple way we learn in primary school......... is there more to it???
ReplyDeletei agree wit the definitions of a variable..but dont we have to link the 14-8 to variables sumhow?like ammm....14-8=x(x being the variable)..and the variable would take the value 6 after calculations..
ReplyDeletei think a variable means exactly what it says...something that "varies"... so if you have a value you want to obtain (the variable) just use it with all the rest of the values you know and by our fundamental knowledge solve for the variable which is the unknown...at least in my veiw... also they just use a symbol or letter to represent the unknown so they won't be any confusion with the variables from the knowns
ReplyDeleteyea i think its changing value to: maybe unpredictable
ReplyDeleteunpredictable hmmmm......... nah..... it is predictable because you can solve for it and you know it is going to be a numerical value so it is known.......... it is like a mystery waiting to be solved.....
ReplyDeletei agree that a variable is an unknown number represented by a letter. e.g question 4, you have $14, you bought 2cds and got back $6, the unknown will be the price of one cd. so you can use X to be the variable to for the equation 14 - 2(X) = 6.
ReplyDeletesooooooo....for all d questions given above we use a variable to solve the equation. since a variable is d unknown. and wel we r looking for d unknown after all.
ReplyDeletea variable is an unknown value and in most cases is represented by usin the letters x and y.In question 2 above, the change is the variable since this is the value that must be found and is the unknown.$14-$8=x(variable)
ReplyDeletewel firstly i would say, $14-$6=2x since we do not know the cost of one cd. so we represent it usin a letter to be the unknown.then this comes down to $8=2x and from here the value of x can be found and this gives you the sum of 1 cd.to fine for both cd's multiply the value u get for x by 2.....
ReplyDelete14-8 are whole numbers. they are values and shows quantity. it can be used in calculations.
ReplyDeletei think a variable is an unknown represented by a letter. i also agree with IQ200 that it can only be known if given in solving an equation eg x=2.
ReplyDeletewell what i know about the word change is that it is the AMOUNT YOU "GET BACK" after you have paid for something. i would say that if you have $14 and something cost $8 the most amount of change you can get back is $2. because to make up that $14 you could have (1st)1 $10 bill and 4 $1 bills OR (2nd)2 $5 bills and 4 $1 bills or simply (3)14 $1 bills. i dont think you can have any more combinations. therefore if you have the (1st) combination you can only pay with the $10 bill and get $2 change. if you have the (2nd) combination you can either pay with the 2 $5 bills and get $2 change or pay with a $5 bill and 3 $1 bills and get no change. if you have the (3rd) combination you can only pay with 8 $1 bills and get no change. there fore i strongly believe you can on get $2 change. if you had ask how much money you would have remained with after buying the sandwich i would hav e simply subtract 8 from 14 and say $6, but you ask about CHANGE.
ReplyDeletehmmmmmmmmmm...... all that explaination you rhel letting the fingers type away yuh thoughts....... just hope it still in yuh head.... lol but seriously, that is some real good examples....... but one thing though....... why letters instead of numbers??? who made this up???
ReplyDeleteI know I does ask the strange and unusually unanswerable questions but someone has to, to at least see who know what...... and me to actually get an answer and learn something.......
ReplyDeletei think it is a number represnting a quantitiy usually what a number represents. of a certain unknown factor
ReplyDeleteIQ200 u asked y letters instead of numbers....think about it like this ...a variable represents an unknown quantity rite..and a number is a quantity...so u cant use a quantity to represent a quantity..therefore a letter is used..nuh sure if daz wat u mean but..i trieddd..lol
ReplyDeleteyea I know that much....... but sometimes they use greek letters ( the funny looking letters ) for a representative too...... so what I want to know is if there is any other things we can use except the letters from our alphabet........ or can we use shortened forms of words.........
ReplyDelete14 - 8...lets apply this to a real life situation...since math applies to real life :P...if i had 14 marbles and i lent 8 of em to Jane then, if i were to count my remaining marbles, id have 6 left...does it get any simpler than tht? :S ...and to include variable...since a variable is a representation of an unknown quantity then we can use the variable in this situation to represent the amount of marbles i had remaining. so if we were to have an equation to represent all this data it wud be x=14-8, x being the remaining amount which in this case is our variable...and...we can calculate for the unknown amount by simply subtracting 8 from 14
ReplyDeleteIQ200, letters are used to represent an unknown value(variable) if we use a number then it won't variable anymore.But y do ppl really use greek letters to represent some variables
ReplyDeletewell animectic I would like to know the same thing but I think it is because it is also letters too...... or they run out of english letters to use.... lol
ReplyDeletequantum100...your answer in explaining 14-8...is exactly how i would go about explaining it..simple and easy to comprehend...good job! :P
ReplyDeletelol...wel i believe that the persons who established formulae use greek letters as their unknown because of d language used at that time. if we considered d time they were living in.....
ReplyDeletenow, greek letters used as variables hv a specific meaning. for example...the greek letter for D, delta, means a change in something.....so greek letters as variables represents something while our common letters like A-Z cann represent and quantity
ReplyDelete14-8..............hmmmmmmmmmmmmmm............... ok lets say we picked 14 mangoes ok, and we ate 8 mangoes frm dat 14, how much wud remain, u do the math lol! So the minus sign (-) simply means we take the number frm in front of the minus sign and simply, remove the amt that is req'd, i.e. the number after the minus sign...........understand!!!! So lets say 4 example, we got a sum: -8 + 10...........wat do we do................well to put it in a more simpler form, we say: +10(frm above) - 8(frm above), instead of -8 + 10!!!!! kool, its d same ting, and i knw alot of us gets confused wen we hav a sum like -8 + 10,even ME, so its d same as sayin: +10 - 8, or 10 - 8, ok??? d plus sign is understood in the sum 10 - 8, so it is not dere
ReplyDeletewell nerd......... that is the perfect name for you since you have all that knowledge flowing out of your mind but I still have to wonder if there is any deeper meaning to the variable....... otherwise that question would have never been asked...........
ReplyDeletewell i really think that a variable dont have 2 be limited 2 just a letter but anything in life that represent something else and a variable dont necessary have 2 be equal 2 a number
ReplyDeleteThis comment has been removed by the author.
ReplyDeleteon number one i agree with quantum100 on the marble theory so the initial equation would be written as 14-8=x with x being our variable. from here the variable would be found by simply taking away 8 from 14 to result in 6x
ReplyDeletex=6
This comment has been removed by the author.
ReplyDeletea variable is simply a representation of an unknown value. usually in most calculations in formulas there are many unknown values to be calculated. these values are not definite until calculated so therfore we use letters to represent these unknown values
ReplyDeletewell i agree with forza it don't have to be a letter of our alphabet... to me it doesn't matter what you name the variable once it is not a number ...think about it why it have to be a letter it could b a question mark....cause to me it means the same thing it just have no value added to it ...when you think about our fundamental knowledge we no the number 2 as being a value to represent something so by putting a number instead of a symbol or letter you will cause confusion that is why they use letters (it simply has no numeric value on its own)
ReplyDeletevariables were developed long ago by greek mathematicians. when they derived formulas to mathematical problems they denoted an unknown by an arabic text, which were the characters they used to avoid confusion of the actual numbers. One of the most arabic symbol used was al-jabir which means "thing". this was taken into old spanish which was written as Xei pronounced as "sei" and was soon abrivated as "x" and today we uses letters to represent any unknowns
ReplyDeletegood reserch boy. i think that a variable is like an unknown, as the name implies it is something i think can vary or change. it can be given to solve for another variable or unknown , for example like when they say solve for y when x=2 in the equation y=2x, u then substitute y=2(2) and calculate to obtain 4 as ur ans. in this example y and x are variables where x is the known variable and y is the unknown variable. the known variable can be varied or changed to obtain a new ans for the unknown variable which is y, that simply means substitute different value for x and obtain different values for y.
ReplyDeleteIf i got $14 and I bought 2 CDs and received $6 change. wats d price of each CD?................
ReplyDeleteSTEP 1: Let the price of each CD be $x
STEP 2: Try to form an eq'n wit d info provided, so, we say: If i got $14 and I bought 2 CDs, this simply means dat, i bought 2 CDs frm my $14........so, this implies........ 14-2x........(ignoring all $ to avoid 'confusion' lol, and makin the SUBSTITUTION, x= price of a CD); and if the change is $6, this implies dat it is equal to 6 (ignoring $).........................
So the eq'n is: 14-2x=6...................kwl?
We now make 'x' the SUBJECT OF THE FORMULA........So we minus six (-6) on both sides of the eq'n.......... this yields, 8-2x=0..............kwl?......................So divididing by 2 implies..... [8/2]-[2x/2]=[0/2]..........so eq'n reads, 4-x=0........ so minusing 4 (-4) on both sides of the eq'n gives.....-x=-4.....So dividing both sides of the eq'n by minus one (-1)................. this implies [-1x/-1] = [-4/-1].............so x= 4.
Recalled dat, x= price of 1 CD, SO A CD COSTS $4.
What is my change if i had $14 and bought a sandwich for $8?
ReplyDeletewell lets let our variable x represent the amount of change we receive after purchasing the sandwich since this in our unknown...
if we were to write this in the form of an equation we wud have:
x = 14-8
(we subtract 8 since it is the amount we wud have gotten rid off after purchasing the sandwich).
from this equation we can now find for x
x= $6
nerd ur calculations are great but i think u cud have made it simpler when u were making x the subject. u cud hav simply say 14-2x=6, carry across the 14 on the right hand side and get -2x=6-14 and u'll get -2x=-8 then carry across the -2 on the right hand side to get
ReplyDeletex=-8/-2. since the -2 was multiplying on the left hand side when it goes across it devides, so u get 4 as ur ans because deviding 2 negative numbers gives a positive number, i think that was much simpler.
Hmmm, a variable is either a number and a letter as 1
ReplyDeletee.g. 4a;
-a letter
e.g. x,y,z, by itself which represents a certain value or somn.
I think...
You could say it's an Unknown number/value represented by a letter (i.e. the letter has a numerical value).
E.g.
4y+8-2x+x=0
4y= a variable.
+8 or 8= a number.
-2x= a variable.
+x(letter)= a variable.
0= a number.
The variables 4y, -2x, +x all have somn in common, the letters represent a certain value.
Depending on the sign in front of the variable will determine whether it is a positive(+) or a negative(-) value.
The numbers 8 and 0 are not variables, since they are already known and specific values. However, if a letter were to be placed after the number then it would be a variable since it is a number and letter as 1 (an existing variable). E.g. 8b or 0d.
Those carry an unknown value, due to the fact that the letter accompanies a number.
Hope you all understand what's a variable now... ;)
i have a question. i wonder if anyone can help me? what is a complex number and why is it important and how does it relate to real life?
ReplyDeletecomplex numbers have two parts a real and an imaginery part. the real part is a number and the imaginary part is a number with a letter. its formula is (a + bi). complex numbers assist in solving polynomial equations of degree one or higher. it is also used in different fields such as quantum physics, electromagnetism ect...
ReplyDeletehey do you get me?????
ReplyDeletei agree that a variable is an unknown number represented by a letter
ReplyDeletei would explain number 1 as a subtraction. taking away one number from another. in real life if a number has been subtracted from another number and the answer is a positive number, this can meen that a loan has been paid off, but if the answer is a negative number then the loan has not been paid off!
ReplyDeletein no 2 my change would be from $14 to $6. i have given away some of my money ($8) in exchange for a product, an now i have 14-8=$6
ReplyDeleteif i bought two CDs at $4 each then both CDs cost $8. and since i had $14 to begin, with i now have 14-8=$6
ReplyDeleteif i have $14 and i bought something and i now remain with $6, this means that the thing i bought was $14-$6=$8. since i have subtracted the total amount of money i had from my change,the remainder is obviously the money i spent
ReplyDeleteTo explain the first question...it comes like u hav $14 and u travel to go home and dat takes $8 from u..the answer for dat is the remaining value. That remaining value we cud find cuz dey reactants, "the quantities used to create the problem, are known..so they are nt variables..variables are unknown and are usually denoted by letters, such as x and y..so u jump out the car or maxi and the amount given to u is ur answer..which everyone shud no is $6..bet u know how to count..so dat is ur remaining value
ReplyDeleteFor question 2 is the same approach.........
ReplyDeleteFor question 3...is basically the same approach..but u first hav to group ur terms..and then subtract...and the value is there..
ReplyDeleteFor question 4, the beginning amt was $14 and 2 items were bought, which we look at as variables..the amt is unknown..which has to be found..and the remaining amt stands as $6. To find the value of one cd...first one has to put as dey equation $14-2x =$6. That is wat the problems tells me. So to find for the unknown values we simply subtract $6 from $14 and get our value which is $8...hey dat is not our final value and de rite answer to de problem...we are looking for one cd..so we divide dat value $8 by 2 and we get x as being $4..
ReplyDeleteThe x represents one cd ..so therefore the amt for one cd is $4...dats how i understand it to be..
that question is very weird to me because i look at things simple once something is equal to something i substitute for eg 14-8=x
ReplyDelete8=x-14 i agree with what IQ200
I would explain 14 - 8 by saying firstly that the sign tells you straight away that the first number is being lessen. So the orignal amount which is 14 is now being reduced by 5.
ReplyDeleteWell darky i think that explanation was kind of vague....
ReplyDeleteI would explain 14 - 8, by firstly explaining the "-" sign which to me in the simplest form means to take off, lessen by...
Now say you have 14 marbles and someone want 8 of them how many i would have now is.
The "o" represents the marbles.
oooooooooooooo -
oooooooo
= oooooo
when u count the remaining marbles u will get 6.
For the second question question i will do it the same way
ReplyDeleteWhat is my change, if I had $14 and I bought two CDs, each $4 each?
ReplyDeleteFirstly i know i have $14 dollars
Secondly i know i bought 2 CDs at $4 each
Therefore the value of both CDs are
CD + CD
$4 + $4
oooo + oooo
= oooooooo
= $8
(the "0" sign represents $1)
Thirdly i will calculate my change by saying since i had $14 and i have to pay for both CDs by paying $8, in which i have to give the person $8 which will lessen my money by $8.
$14 - $8
oooooooooooooo - oooooooo
= oooooo
= $6
Very good explaination Swanky Thing and as can be seen a variable is used as a substitute for an unknown number
ReplyDeleteYep i believe a variable can be used to subsititute for an unknown
ReplyDeleteHey miss i just wanna make sure you have my info.........
ReplyDeletemy ID number is 109002131
a variable is a number used in place of something
ReplyDelete$14 - $8
ReplyDeleteyour change would be =$6
14-8=6
ReplyDeleteyou had 14 apples minus 8 apples then your remainder wiil be 6 apples
amt. of momey = $14
ReplyDeletecost of sndwich = $8
therefore change = $14 - $8
= $6
amt. of money = $14
ReplyDeleteno. of cd's bought = 2
change received = $6
therefore cost of one cd = $14 - $6
= $8/2
= $4
Hey!
ReplyDeleteA variable is essentially the "unknown" of a problem. Variables in algebra are represented as letters of the alphabet. Examples: x, y, z.
For example, if you had this problem:
"Jake had three pencils. His pencils and Julie's pencils together came to 7 pencils. How many pencils did Julie have?"
The unknown, or what you are trying to find, is the number of Julie's pencils, right? So we can use 'x' to represent Julie's pencils.
How would you find Julie's pencils? Well, the total number of pencils, 7, was got by combining (adding) both Jake(3) and Julie's(x) pencils.
In an equation, that would be:
Julie's + Jake's = Total
x + 3 = 7
-3 -3
x=4
Julie has 4 pencils.
Hope this helped you understand!