|If an odd number is subtracted from an even number, then the remainder is odd.|
|Let the odd number BC be subtracted from the even number.
I say that the remainder CA is odd.
|Subtract the unit CD from BC, therefore DB is even.||VII.Def.7|
|But AB is also even, therefore the remainder AD is also even. And CD is a unit, therefore CA is odd.||IX.24
|Therefore, if an odd number is subtracted from an even number, then the remainder is odd.|
Next proposition: IX.26