How timely. After reading Devlin go on and on about addition and multiplication being different operations, DD brought home some vocabulary homework from her math class, and needed help looking up the various properties of operations, since they don't show up in her dictionaries.
And so we came to "identity property," and I immediately exclaimed, "Which one?"
Addition: n + 0 = n
Multiplication: n x 1 = n
They're totally different rules. Here was an immediate illustration of how thinking of them as totally different operations can help make sense of them.
Product and divisor were on the word list, addend and sum were not, so I assumed they wanted the properties of multiplication.
