I’m working on a 1st grade math book with tables. The person who did the English version spurred horizontal lines. It makes sense for tracking, especially since the table is shapes. Couldn’t find a rule.
Tables in first grade math books are done according to Braille Formats and Nemeth Code. So you would use the regular boxing lines (if needed) and the standard column heading separation line. If you are double spacing the book, do not double space in the table.