1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Complete noob here :P

  1. Jul 27, 2010 #1
    I'm learning Algebra (the basic and foundation of Math) 'cause I stink. Now I'm just doing some review from the beginning before I get into the tough stuff.

    I'm a bit stumped on factors and multiples. I understand it but not clear enough. I couldn't give you a definition and if you asked a tricky enough question, I might get it wrong.

    Can someone explain it???

    What I understand:

    If a question ask what are factors of 20, I'd give numbers that can be divided to 20 and get an even answer. So when I type in 20 in my calculator, and then the "/" the number that I put in after the "/" should give me an even number, if it does, then it's a factor. So ex, I'd go

    Factors of 20: {1,2,4,5,10,20}

    1x20 = 20
    2x10 = 20
    5x4 = 20

    that's the reason why I wrote 1,2,4,5,10,20 up until I started studying this like today I always that when someone asked that question you'd just say 1,2,5,10,20 I would never have included the 4.

    Multiples, based on the example the book I"m using gave, you simple just list the times tables for that specific number ex:

    Multiples of 2 = {2,4,6,8,10,12,....}
    the book didn't include 1 for the multiples but it did for the factors. So why is that we put 1 for factors and not multiples??

    Lastly there was a question:
    {y| y is a natural number multiple of 7}

    the answer was {7,14,21....}

    if it was "y is a WHOLE number multiple of 7" would the zero have been included??
  2. jcsd
  3. Jul 27, 2010 #2
    This is the correct definition, assuming you mean "an answer that has no remainder" by "an even answer", and those are all the factors of 20.

    Why would you have not included the 4? It fits the exact definition you gave. Mathematics is very precise in this way; there is no leeway given over a definition that is not vague.

    That is also a good definition.

    It does not fit your definition. What position on the 2 times table does 1 occupy? In other words, which multiple of 2 is 1? The first multiple of 2 is 2 (1x2 = 2), the second multiple is 4 (2x2 = 4), and so on.

    Yes, 0 is a whole number, and 0*7 = 0. Turn to the definitions for justification.

    It is impossible to determine the truth of any mathematical statement if it is not a definition, and thus defined to be true, or follows logically from a collection of definitions. If you find yourself doubting a result, you can only verify whether it is true or false by looking at the definitions or theorems that preceded it.
  4. Jul 27, 2010 #3
    Thank you soooooooooooo much. I really appreciate this. big props :cool:
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook