Math Is Fun Forum

paulb203

Member

Registered: 2023-02-24

Posts: 323

Proof

Maths Genie;

Show that, when a and b are both odd numbers, the value of 2(a+b) will always be a multiple of 4

My answer;

Odd+Odd=Even
2(a+b)=2(odd+odd)
2(odd+odd)=2(even)
Even = 2n
2(2n)=4n
4n=multiple of 4
QED

Q.Is this correct?

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Their answer;

Odd+Odd+Even
2(Even)is a multiple of 4

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Q. Is their answer enough, to be considered a proof?

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Prioritise. Persevere. No pain, no gain.

Bob

Administrator

Registered: 2010-06-20

Posts: 10,627

Re: Proof

Is their answer good enough?  I'd  say no .... a lot has been left out.  Your proof is much better.

Bob

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Children are not defined by school ...........The Fonz
You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei
Sometimes I deliberately make mistakes, just to test you!  …………….Bob

paulb203

Member

Registered: 2023-02-24

Posts: 323

Re: Proof

Thanks, Bob.

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Prioritise. Persevere. No pain, no gain.