Pages doesn't have an automatic label function - if this is an important feature to you use the feedback option in Pages to request it. I've simulated the function quite simply and as long as the document isn't too long it works okay. Insert the formula, graphic or whatever and in the text type your label text sans number. In my draft I insert the graphic as in inline object with the label text immediately following.
Now that I've finished all my editing I go back and label the graphics. Starting at the top of the document I search for my label text which jumps me to my first label. I select the graphic and make it floating. Now I insert a text block, type my label, format the text and resize the text block. The last prep step is to copy the text block so I simply have to paste it for the rest of my graphics. I place the text block beneath the graphic, group the two, and place the grouped object in the document where it belongs. Finally, I edit my generic label text in the document to match the label I just created. Now I can do another find, paste the text block, etc.
It sounds worse than it is and for me doing this with about 10 graphics is worth not being forced into using Word. Oddly enough, being a programmer and having cut my teeth doing word processing on a Digital PDP-8, I never did warm up to LaTeX.