Hi !
Thank's for your question :)
Here is a very simple thing that will help you a lot !
So we have :
-30 + 3
All you have to do is reverse the addition. you have to subtract. Don't focus about the least in front the 30 for now.
So :
30 - 3 = 27
Then you just put the least in front !
Like this : - 27 Tadam !!
It's will be the same thing if you have a exemple :
-30 - 3.
You you have to do is reverse. So you have to do a additon.
30 + 3 = 33
So we put after the least, very IMPORTANT to not forget ;)
30 + 3 = - 33 !!
I I hope I helped. And that you understand what I wrote to you in English haha
Have a nice day !
BrachiosaureTimide314