Final answer:
The parts of an expression separated by a plus or minus sign are known as terms. Plus and minus signs indicate addition and subtraction, respectively, and each term must have the same dimensions to be combined.
Step-by-step explanation:
The parts of an expression separated by a plus or minus sign are called terms. In mathematics, we use these symbols to perform operations. When you see a plus sign (+), it indicates the addition of two terms, while a minus sign (-) indicates subtraction.
For instance, in the expression 4x + 5y - 3, we have three terms: 4x, 5y, and -3. When dealing with multiplication and division, we follow specific rules related to the signs of the numbers involved. Plus signs also appear in chemistry, where they separate individual reactant and product formulas in a chemical equation.
It is important to note that each term in a mathematical expression must have the same dimensions, meaning we cannot add or subtract quantities that are not alike, such as adding length to time.