Which operation is defined as the opposite of addition, decreasing one quantity by the value of another quantity?

Subtraction is the operation defined as the opposite of addition. When you perform subtraction, you decrease one quantity by the value of another quantity. For example, if you have 10 apples and you take away 4, you are subtracting 4 from 10, resulting in 6 apples. This is a direct contrast to addition, where you would combine quantities to increase the total.

In mathematical terms, if addition combines values (e.g., 2 + 3 = 5), subtraction reverses that process by removing a value from a total (e.g., 5 - 3 = 2). This fundamental relationship between addition and subtraction is critical to understanding basic arithmetic and number concepts, laying the groundwork for more complex mathematical operations.

Finding the operation that specifically describes the process of removing a value from another justifies why subtraction is the correct answer in this context.