Math Coach's Corner: The Meaning of the Equal Sign. Ask a kiddo who has just written 2 + 3 = 5 if it's okay to write it 5 = 2 + 3 and you're likely to get an emphatic NO! Enter common core standard 1.OA.7: "Understand the meaning of the equal sign, and determine if equations involving addition and subtraction are true or false. For example, which of the following equations are true and which are false? 6 = 6, 7 = 8 - 1, 5 + 2 = 2 + 5, 4 + 1 = 5 + 2."