I'm looking at a model and it's feeling like it's pretty finished. Whenever I think that I've finished a piece of work, I always like to check it, and if I can, I'd like to put some checks into the budget.

Let's look at one that's standing out at me.

I can see the number of short and long haul flights in course one are 150 and 50. I'd like to check that that accounts for all 200 of the participants. If we came to a different number, whoa, that might mean that I have accidentally missed out one or two or many of the participants. So I'd like to insert some new rows and then I'll put those calculations in. If I select row 43 and I insert a row, it will try to grab the formatting from the cells above, but I'm not putting in any assumptions here. I'm going to be doing calculations. Calculations should be black font on a white background, so I'm going to grab, row 44. I select that with my mouse. Then right click insert, and then I do that a second time and it's grabbed the formatting from the cells above which were white. Brilliant. Let's calculate the total number of flights, and underneath that we'll do a check. So my total number of flights, I'm going to sum that up. It's the 150 and the 50 close bracket, and I like a lovely consistent formula. I can drag that to the right. I'll have exactly the same formula for course two. I notice in column E that we were summing to the left, summing to the left. I'd like to do the same thing for the total number of flights. So I want to copy this formula from E38. I'm going to do that by pressing control C, so I hold the control and then press the C. That copies, I go down to E43. I want to paste, so I press control V and I hold the control and press the V.

Lovely. So column E is the summing to the left column. Great. Now to do my check and I'm just going to press equals go up to the total number of participants of 200, and I'll subtract the total number of flights.

If I get a zero that suggests to me that I've got the correct number of flights for the participant numbe. Press enter and I get a zero. Amazing. Let's drag that to the right. We'll have a nice consistent formula across this row, and I see for course one, we've got zero for course two, a zero, And in column E, I can see the total is zero. Great. Now a bit of a decision to be made here in column E we've been summing to the left, summing to the left, summing to the left. You could, of course, down in E44, you could have summed to the left instead of doing the same subtraction that we had in column C and D. A judgment call on that one.

Lastly then, I just want to make sure that no one links to the these check cells. I don't want anyone thinking that these are numbers that should be going into calculations. The way we can do that is firstly, we can make it a light gray font color, so up to the ribbon, choose font color gray, and secondly, make it italics.

Fantastic. My budget's all done with checks in as well.