 Hello, this is Professor Steven Nesheva, and I want to share a little bit about how to do this thing called fill down Which will save you a lot of time In your spreadsheet. So I've got I've got an ideal gas kind of law kind of calculation going on here I'm going to double-click on this cell here. You can see that it's To calculate P times B. I'm saying go to cell B 14, which has the pressure and multiply by B 15 Which has the volume and and that's fine. It entered that number there What if I want to do that for the next for the next row here? Well, I could Go to the right-hand side and click and drag on that and now what I want to show you is what happened is that? It automatically advanced those those cell references to instead of being to 14 and 15 Which is pressure and volume it moved it ahead to 15 and 16. That's not what I wanted So I need to find a way to defeat that that automatic Adjustment and the way you do that is you put dollar signs in front of it So I'm gonna say dollar B dollar 14 times dollar B dollar 15 Okay, and and now when I drag that down You can see what happens is that it keeps it at Referring to those those those cells and so now I can do that all the way across here I can do the same thing here and Now this is supposed to be R times T Which is cell 17 times 16? But and when I fill that down, I want to I want to fix those numbers those references So I'm gonna do dollar B dollar 17 dollar B dollar 16 And now I'm gonna pull that down. There is a kind of a trick if if you have a bunch of numbers on the left here And I want to fill down I could just drag it like what I did before but it turns out double-clicking on that does the same thing Now there's one more thing. I want to share with you sometimes you do want it to advance the The reference so here for example what I'm doing is I want to get PV divided by RT So that cell D to divided by cell D e2 and and here what I want to do is I want to take these values of PV and RT and and and and Have that automatically advanced and so now you see it did advance to row 3 D 3 times e3 and I can do that again Here's D 4 divided by e4 and so on now in this case Doesn't look like we're getting very much difference in the in the in that ratio PV over RT, which is something that we'll want to talk about