Conditional addition

In my spread sheet I have multiple columns - labeled -

hours / module / hours / module / hours / module
4 / 1 / 2 / 2 / 6 / 3
4 / 1 / 4 / 2 / 4 / 4
4 / 2 / 4 / 2 / 4 / 4

each row = a week in a year

module 1 = total hours worked ?????
module 2 = total hours worked ?????

The modules are schools modules, which need to be completed by each student. The hours column on the left of the module column indicates the hours worked in that module. (the above example - 4 hours worked in Module 1 / 2 hours worked in module 2 / 6 hours worked in module 3).

What is the most effective way to create an automatic calculator that adds up all of the hours worked in each of the Modules

How many hours worked in module 1
How many hours worked in module 2 etc??

EDIT: below was based on your initial sample of data (ie week1, week2, week3 in first column)

the layout of your data is not I'm afraid particularly conducive to easy analysis

If we assume your present layout is in range A1:G4 with headers in B1:G1 and weeks in A2:A4 then to sum say module 1

Module1:
=SUMPRODUCT((MOD(COLUMN($C$2:$G$4),2)=1)*($C$2:$G$4=1)*$B$2:$F$4)

the text in red can be a cell reference containing the module number of interest.

Based on your sample file...

First you should correct O26 - should be 25 rather than 24.

Then based on your modules (numbers with exception of "A") you can use

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The above (in essence)y checks that the column of each cell in the range referenced is odd (C,E etc) and that the value within the cell being iterated equals Module of interest and multiplies the numerical value from the cell to the left of the cell being iterated by 1 or 0 depending on whether both prior conditions held true (ie module match and column being processed is odd).

The SUBSTITUTE is used to handle the fact that some cells within the range contain "A" (removed) and the 0& to account for the fact that some will be blank/null

Both features combined ensure that when the value in the cell to the left is * by 0/1 the value is numeric in nature... if not the SUMPRODUCT would generate a #VALUE! error eg:

TRUE*TRUE*"a" --> #VALUE!

whereas

TRUE*TRUE*"0" -> 0

(Boolean TRUE/FALSE when coerced become 1/0 respectively)

No problem. FWIW I have since your last post rephrased my prior reply for sake of clarity (I hope?)

On an aside please also remember to mark thread as solved if you're happy you have a workable solution.