Sometimes when writing math you realize that a minus should be a plus, or vice versa. For the former, it's quite easy to convert the $-$ into a $+$. You simply need to add a vertical line through it.
For a plus that you want to turn into a minus, it's not that easy. Here are some things you could do:
- You could add a minus next to it, because $+-=-$. However, a lot of the time you don't have the space to do so! It also makes it a bit more confusing sometimes than it should be.
- You could cross out the plus and then put a minus above it. This makes it messy, but other than that it's the best of the two options.
- Of course, you can always cross everything out and start over again, but this is something that I'm trying to avoid (hence the question!).
So my question is, is there any sort of sign that indicates a minus that you can easily convert a plus into? I was thinking something like $\boxplus$. It would be very easy to convert a $+$ into a $\boxplus$ simply by boxing it, but I would have to define $\boxplus$ to mean a $-$ and then explain that to my teacher so that I didn't get any weird looks. Is there any symbol which mathematicians use for this? What is your preferred method of changing a plus to a minus?
Also I wanted to add, this does seem a bit like a trivial question, and it is, but I have wondered it for a few years now and I couldn't think of a better community to ask! It's just curiosity.