In addition to helping students avoid the thirteen rules that expire, we must also pay close attention to the mathematical language we use as teachers and that we allow our students to use. The language we use to discuss mathematics (see table1) may carry with it connotations that result in misconceptions or misuses by students, many of which relate to the Thirteen Rules That Expire listed above. Using accurate and precise vocabulary (which aligns closely with SMP 6) is an important part of developing student understanding that supports student learning and withstands the need for complexity as students progress through the grades.