I'm in 7th grade and I learned in chapter 2 that if there is two negatives (ex: 9 - - 2) you have to make the two negatives a positive, this is called "add a line, change the sign" therefore my example would equal 11. Your question 9 - (- 1/2) would actually be 9 + (+1/2) it's that easy So the answer would be 9 1/2 ( positive) I hate math but that's one of my fav tricks!
Make the two negatives a positive since they are right next to eachother. that would then be: 9+1/2 Which you would then use normaal addition for and it would add up to: 9 1/2 or 9.5
