Hi Tina. You are not the first person to wonder about this layout in the lesson book--I am sure your question will be appreciated by many readers of this forum.
In "An Introduction to Braille Mathematics," the numbers in parentheses organize the EXAMPLES but are not to be seen as ITEM NUMBERS. You will never see those numbers in the simbraille. If the example is illustrating itemized material, you will see the item number or letter separate from the example number. Look at the first FORMAT example (1) in Lesson 1, page 8, Section 13, to see what I mean.
As you know, there is no 1/1 paragraph format in the Nemeth code, unless of course it is a continuation of a paragraph following an interruption of some kind. You can assume that -- unless formatting is under discussion -- the example sentences are taken out of context of any formatting.