# MS Word: Listing captions of equations in MS Word with extra Heading level

I have several equations that I would like to list using captions. I created a new caption label, called 'Eqn.' where the numbering follows Chapter Heading 1, in order to follow the chapter list. for example:

``````Chapter 1
d*S* = >= 0 (Eqn. 1.1)
E = mc^2 (Eqn. 1.2)
Chapter 2
a^2 + b^2 = c^2 (Eqn. 2.1)
``````

Suppose I need to modify Eqn 1.2, and show it as it is solved for m. I want to name the same two equations with the same number (i.e., 1.2) but with a different label (e.g., using letters), for example:

``````    Chapter 1
d*S* = >= 0 (Eqn. 1.1)
E = mc^2 (Eqn. 1.2A)
m = E/c^2 (Eqn. 1.2B)
Chapter 2
a^2 + b^2 = c^2 (Eqn. 2.1)
``````

of course, I want all the captions to be automatized and consistent

You can achieve this numbering, but it can't be entirely "automatized" without losing some of Word's built-in facilities. Initially, I'm just going to try to address the specific situation that you have described, i.e. you sometimes want two successive equations labelled with the same number but with A for the first and B for the second. If you are actually looking for something more general than that, e.g. you might have A,B,C or the related equations are not necessarily immediately after one another,

1. You may need a more complex scheme and
2. You will need to describe your requirement in more detail and think about whether you are willing to lose certain Word features.

Normally, if you define a Caption label "Eqn." and use chapter.caption numbering with (say) Heading 1 style paragraphs as your headings, Word will use the following text and field coding to insert your captions

``````Eqn. { STYLEREF 1 \s }.{ SEQ Eqn. \* ARABIC \s 1 }
``````

(Where all the { } are the special field brace pairs that you can insert on Windows desktop Word using ctrl-F9).

Maybe you are inserting brackets manually around the caption like this

``````(Eqn. { STYLEREF 1 \s }.{ SEQ Eqn. \* ARABIC \s 1 })
``````

but let's leave that aspect to one side for now.

AIUI what you want is to be able to have a sequence of equations numbered like this

``````Eqn. 1.1
Eqn. 1.2A
Eqn. 1.2B
Eqn. 1.3
``````

So at first sight you could achieve that by modifying the caption for 1.2A to be like this

``````Eqn. { STYLEREF 1 \s }.{ SEQ Eqn. \* ARABIC \s 1 }A
``````

and the caption for 1.2B to be like this

``````Eqn. { STYLEREF 1 \s }.{ SEQ Eqn. \* ARABIC \c }B
``````

because the `\c` option just says "use the current number in the `Eqn.` sequence"

But, if you have created your Table of Eqn.s in the usual way (by inserting a Table of Figures and selcting the Label `Eqn.`), it won't actually pick up the 1.2B caption, because it just does not recognise a SEQ field with a `\c` option.

One way to fix that is to apply a specific paragraph style (say, "Eqn" to your Equation captions, and generate your Table of Equations using that.

Another is to modify the code for the A and B captions so that the Table of Eqns. The most obvious possibility is:

``````Eqn. { STYLEREF 1 \s }.{ SEQ Eqn. \* ARABIC \s 1 }{ SET XEQn { SEQ Eqn. \c } }A

Eqn. { STYLEREF 1 \s }.{ SEQ Eqn. \* ARABIC \r { XEQn } }B
``````

For two equations A and B it doesn't really make sense to try to generate the A and B using any kind of { SEQ } numbering. If you do, the first SEQ typically has to reset the sequence using `\r 1` and the second one does not. But it is no simpler.