I am not sure when the school teaches Roman numerals. Obviously it wasn't third grade because my DS10 has not learned anything about it (He's going on fifth).
It's great that your kiddo picked up knowledge of
Roman Numerals as if by osmosis.
Common Core standards do not include
Roman Numerals. A quick perusal of the
Common Core Math Standards, a search of the
93-page downloadable CCSS Math Standards PDF file, and a use of the
Common Core search tool for "Roman" in Math Standards do not find this topic.
If schools do not go beyond Common Core to teach this concept, then parents hoping for their children to become familiar with
Roman Numerals may want to expose their children to the concepts and/or simply point out
Roman Numerals when they see them IRL. This old
blog post from 2013 mentions several contexts for the
use of Roman numerals... including the Super Bowl, Olympic games, names of persons (such as Queen Elizabeth II). I can think of a few more: some styles of analog watches, clock faces (especially grandfather clocks), page numbering in book prefaces, formal
outline formats.
A few resources:
1.
Life of Fred covers
Roman Numerals in 5th grade, along with Fractions.
2. I like this
RapidTables Roman numerals[/color] chart as it contains all I need to know, in a concise format.
3. Another resource for learning [color:#660000]Roman Numerals is a video (length 5:49) currently found through
HippoCampus. Current navigation to the topic is as follows: Select MATH... Arithmetic... WHY-U Collection: Pre-Algebra Foundational Concepts...
Roman Numerals: Sign-Value versus Positional Notation.
Wikipedia has a page on
Roman Numerals here, which unfortunately seems to dismiss
Roman Numerals as being somewhat obsolete... which may be reflective of
Roman Numerals not being included in Common Core.