 So if you memorize one of these formulas you don't have to memorize the other one because you can just convert back and forth, so in this case we've isolated the Fahrenheit variable, but when we Convert the equation we can isolate the Celsius variable, so let's do that. So the first thing we're going to do order of operations right is subtract 32 from both sides so minus 32 32 So when we do that that cancels that out. So what do we have now? We've got degrees Fahrenheit minus 32 equals 1.8 times degrees Celsius. So is degrees Celsius isolated yet? No So how do we do that? We've got to divide both sides by 1.8 Cancel and of course that is now isolated degrees Celsius, okay, so It's a very stress And there's the formula that you want to use for degrees Celsius So again, you can inter-convert between the two formulas. I recommend memorizing as little as possible because I don't think you really Chemistry is about something that you kind of want to understand, you know Do step by step and if you start to memorize a lot of things you just get a lot of facts in your head and it gets But anyways, uh long story short. Let's just use this formula to plug in to figure out what our temperature in degrees Celsius is going to be all right, so now that I have the formula written Can just look over there notice the decimal point here negative 10 Decimal point. So like I said, I just convert the units straight away Um, so negative minus 32 divided by 1.8 And then gives me on my calculator negative 23 point three three three three three repeating until infinity Degree Celsius, but that's not what we're going to use why because We've got two sig figs here. So when we do the All of our division part, we're going to have to Put our answer to two sig figs to 23 degrees Celsius if you don't use Fahrenheit units then um Like if you're not in the US then I guess you don't have to worry about this, but if you are Then you do so Good luck to you