Let number of prs of trousers bought = x
If Mary has £60 and price of trousers=£12
How many prs of trousers can Mary buy
Usually we leave out the 1 and write x=5 QED
So Mary can buy 5 pairs of trousers.This is algebra
Is it sensible to buy 5 pairs of identical trousers? That is not mathematics.It might be common senses,ethics,foolishness or wisdom.
That is a more complex question like” buy 2 get one free” when you don’t even need one!
Further,should Mary draw her life savings out and buy 1,000 pairs of trousers?
Clearly not so where should she draw the line? Because ladies get tired of their clothes and how long is Mary going to live? And she is depriving 999 other ladies of a pair of trousers as well.That is worth thinking about but it’s not mathematics,is it.
From this we can conclude that algebra is easier than other problems we deal with/Amen