Chapter 1 - Foundations for Algebra - 1-1 Variables and Expressions - Practice and Problem-Solving Exercises - Page 7: 20

A good phrase to use would be: "The sum of 49 and a number m."

We are given the expression 49+m. These two things are being added, so we use the math term "the sum of" and list the two things we are adding, 49 and m. Therefore, we say "The sum of 49 and a number m" to denote the expression.