Reborn in 1995

I am a novice writer, so I hope you can bear with me. If you have any opinions, please feel free to express them directly. I also hope that you will urge me to improve!

Chapter 4, 90 divided by 5, plus 180 minus 10, does it equal 198???? Shouldn't it be equal to 188? Is it because I didn't study well in primary school?

Let's see how it goes, I hope it's not too toxic.