The other day my 6th-grade math group was wrestling with the question of whether ‘zero’ is odd or even. Three comments stood out: William maintained that zero can’t be even because it cannot be divided by two, so it must be odd. Vivienne said that zero must be even, because odds and evens alternate, and zero is between plus one and negative one. Then Milo said that zero is nothing, and so it can’t be even or odd.
This is just the kind of discussion that makes teaching worthwhile. The small group - there are only six children in it - continued to debate the question. William, for example, said that the fact that evens and odds alternate is not the definition of evenness, only one of the properties of odd and even numbers, while Milo expanded on his comment by saying that nothing cannot have any properties, including odd or evenness.
Of course, the textbook has an answer, and the children know how to deal with zero when they see it in a number, but I thought it was much more interesting to leave the question open and unresolved than to tell them what was ‘right’. Ultimately, we have to answer the big questions for ourselves.