If as many odd numbers as we please be added together, and their multitude be even, the whole will be even.
For let as many odd numbers as we please, / A B /, / B C /, / C D /, / D E /, even in multitude, be added together ;
I say that the whole / A E / is even.
For, since each of the numbers/ A B /, / B C /, / C D /, / D E / is odd, if an unit be subtracted from each, each of the remainders will be even ; [G.352]