Prove that the sum of four consecutive whole numbers is always even.
In your working, let your first number be n.

Step-by-step explanation:

hello :

let four consecutive whole numbers :   n  ,  n+1 , n+2  , n+3

the sum is :  n  +  n+1 + n+2 + n+3 =4n+6

you can write 4n+6 to the form : 2(2n+3)    means   2k    ( k=2n+3)

so even number  

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