Proof about addition commuting

[cragar]

Homework Statement

Prove by induction that 1+a=a+1 for all natural numbers

The Attempt at a Solution

basis step 1+1=1+1
Now we assume that it is true for a=k and then look at k+1
I first wanted to do this (k+1)+(k+1)=(k+1)+1 but that doesn't give me the right answer.
so should it be (k+1)+1=(k+1)+1
on the left side am I just adding 1 because we are looking at the next term
and on the left side i replace 1+a with k+1 because we are assuming that holds and then looking at the next term.

 

[LCKurtz]

Homework Statement

Prove by induction that 1+a=a+1 for all natural numbers

The Attempt at a Solution

basis step 1+1=1+1
Now we assume that it is true for a=k

Write down what that means so you know what you are given.

and then look at k+1

Write down what you are trying to prove.


That should get you started. Do you have the associative law to work with?