This document appears to be notes from a math lesson on using identities and inverses to write equivalent expressions. It includes examples of adding and multiplying expressions with their inverses. Key points covered are: - The additive inverse of a number is its opposite, and the sum of a number and its opposite is 0. - Zero is the additive identity, meaning it leaves a number the same when added. - The multiplicative inverse of a number is its reciprocal, and the product of a number and its reciprocal is 1. - One is the multiplicative identity, meaning it leaves a number the same when multiplied.