Using the Polynomial store to understand addition and subtraction of terms
Like terms can be added or subtracted but unlike terms cannot be added or subtracted. Let us understand this using the concept of a polynomial store.
A store called the polynomial store sells red square tiles, red cube-shaped stools, wood chopping axes, green tea, yellow tea and a combo pack of square chocolate and cube-shaped toffee.
This is the inventory of the products in the morning is as follows:
Inventory in the polynomial store
Here, the products can be considered as a term. So the variables are the products and the coefficient of the variables that we see is the quantity of the products.
Thus, there are 25 red square tiles ( 25𝑟2 ), 15 red cube stools ( 15𝑟3 ), 10 axes (10x), 52 boxes of green tea (52g), 78 boxes of yellow tea (78y) and 100 combo packs ( 100𝑐2𝑡3 ).
During the day, items sold are as follows:
3 red square tiles ( 3𝑟2 ), 5 boxes of green tea (5g), 25 boxes of yellow tea (25y) and 25 combo packs ( 25𝑐2𝑡3 ).
To check the end of day inventory, all items sold must be subtracted from the appropriate quantity from the morning.
This means 3𝑟2can be subtracted only from 25𝑟2. 3𝑟2 cannot be subtracted from15𝑟3. This is because if the red square tiles are sold, then it’s the number of red square tiles that will be reduced and not the red cube stools.
The items sold during the day can be calculated as follows:
Inventory after sales of the day
When fresh supplies are brought in, each quantity is added back to the appropriate products.
A point to note here is that, if the truck delivers a stock of 50𝑡3𝑐2, it is not a different product item. They are the same packs of square chocolates and cube-shaped toffees. So it can be added to the stock of 𝑐2𝑡3.