Looking at subtraction

The reduction structure

The reduction structure is similar to take away but is associated with different language. It is simply the reverse process of the augmentation structure of addition. It refers to a situation in which a quantity is reduced by some amount and the operation of subtraction is required to find the reduced value.

For example, if the price of a bicycle costing €149 is reduced by €25, what is the new price? The essential components of this structure are a starting point and a reduction or an amount to go down by. It is this subtraction structure that lies behind the idea of counting back along a number line.

Realistic examples of the reduction structure mainly occur in the context of money. The key idea that signals the operation of subtraction is that of ‘reducing’, for example, reducing prices and costs, cutting wages and salaries.