Which type of number includes a decimal point to indicate values less than one?

The correct choice is a decimal number, as it explicitly refers to numbers that are written with a decimal point, which separates the whole part from the fractional part of the number. This representation allows for precise values that are less than one, such as 0.5 or 3.14.

When discussing whole numbers, these are defined as non-negative numbers without any fractional or decimal component, including zero (0, 1, 2, ...). Integers extend this concept to include negative whole numbers as well, still without decimals (e.g., -3, -2, -1, 0, 1, 2, 3). Real numbers, on the other hand, encompass all rational and irrational numbers, which includes decimals, but is a broader category that also contains whole numbers and integers. Therefore, while real numbers can include decimal numbers, the specific reference to a decimal point is best captured by the term "decimal number."