An expression is a mathematical phrase. Expressions are different from equations because they do not have values on both sides of an equal sign. An expression contains a combination of terms and operations. They can be as simple as 4 + 10. That expression has two terms (4 and 10) and one operation (addition). Which of these is a mathematical expression? A 1 - 15 B 1 and 15 C 1 - 15 = -14 D “Raining cats and dogs”