Focusing on your studies will help you in life even though you have to listen to a boring teacher talking about something you think is useless. Hey everyone been there. Well good grades will lead you to the right path in life for example colleges and university probably except you if you're an a or b student instead of a f or d student. Many people or young children think What the point of this or WHY do we spend all this time on school versus other things.Well concentrating on your studies, you can get an idea of what is out in the world. It can help you can figure out if this job worth staying in. What say a job pays you 2 dollars for four hours and another job pays you 4 dollars for four hours that a better deal. Also this example is not realistic.
Also if you’re good at math you can figure out the cost of things so you can be sure you're getting what you're supposed to or maybe the opositel. You do not want to give someone less than they deserve. Also you need math to pay your taxes and other stuff. If you live with a roommate, you can divide the expense and calculate out how much you and your roommate both.
So you see, having good grades is not bad, there is more good than bad.