My ex-colleague asked me some questions on how to do her new job in a better way. To make you understand the importance of Mathematics learnt in school but at the same time to protect her working privacy, I use a simplified version of the problem that she faces.
Her company is selling packet drinks and she takes care of the inventory of the packet drinks. She already has a table to record the quantity of different flavours of the packet drinks, but she cannot get an accurate inventory sometimes. I found out the problem immediately after she told me that she used different units in the same table.
At school, we learn that we must always use the same unit for calculation. In the same operation, we cannot mix minutes and hours (different units in time). If the question gives you different units, you must change all to the same unit, preferably one that is easy to work on. It is important to use only one unit because you may get yourself confused with different units and a wrong answer.
We learn to prepare ourselves for the working world. The use of only one unit in a particular question may seem like a small matter, but you will see the problem when you are at work.
Back to my ex-colleague’s problem. Her company has loose packs, which is counted one by one, and 12 packs in a box. In the column for loose packs, she uses 1 as 1 pack. On the same table, in the column for 12 packs in a box, she uses 1 as 1 box, where 1 box has 12 packs. The units are different! If she adds 1 pack and 1 box, she does not get 2, she gets 13 packs.
The solution? As long as she uses only one unit in the same table, she should have no problem in getting the final inventory.