Maintenance Formula for Incrementing Values

Hi Forum, so I am looking to see how I can have a spreadsheet to where I have pre-existing data already and in one cell I have the current value (we will say 5186.4). What I am looking to do is make it where I can in the left adjacent cell enter a value and it will populate the sum of Cell A(5186.4) with the new value from Cell B(new data). The condition is that I need the new value to be retained as the new "default value" for Cell A so when I open up the spreadsheet for the next days daily maintenance report, it will report the new value so all I have to do is enter the new data in Cell B and it will keep populating and saving the new value into Cell A..

For example:
my power generator engine has 5186.4 miles. On Day 1 I ran the engine for 16.1 hours so the new engine hours are 5202.5 miles. But when I input new data for day 2, it would say I already have 5202.5 hours and the hours run were 20.4 so it takes the new default of 5202.5 and adds the new value of 20.4 to create 5222.9 hours on the engine and so forth. I can understand and am all for using a behind the scenes formula that takes place on other cells that are hidden when i print out the maintenance report. I just need it because doing all the calculations i need to for all my engines and such is time consuming since i have to constantly input the values for all my engines.

the issue i have is that on the main sheet page where all the daily maintenance is reported I only have 2 cells to work with.



Last 24 Hours Total Engine Hours
16.1 5186.1

so when I put in the 16.1 it took the old value and added it to get me the 5186.1

so what I am looking for is that when I enter in the new value into Last 24 hours, it will calculate the values and reflect the new default value into the Total Engine Hours Cell

But i need it to save the new values so when I go in the next day it will look like this

Last 24 Hours Total Engine Hours
20.2 5206.3

etc

so the only value I deal with is the Last 24 hours cell

Make sense?

I appreciate the help. But I'm just learning excel through trial and error so learning VBA into a project that I am only working with for 2 more months. Ugh

Andy, could you post an example workbook?
The data included is not so important (but should be representative of what will be in the real file), but the layout must be what you're currently working with.

As far as I see it, there are several ways of doing this with some simple VBA in the background. You wouldn't even need to write the code, you could get Excel to do all that for you with the built in macro recorder.

Badly, attached is the sample portion of the workbook (outline is there but had to change the names and such due to it being of corporate sensitive material (gotta love contracts). Essentially what I would like to be able to do is look at whatever macro or VB that is used and be able to see how its done so that I can incorporate similar calculations into other workbooks that I am working on.