Charlotte Mason's approach to teaching - not the curriculum - but the actual teaching - is unique to the homeschool world and the subject of Math is no exception. For this subject, she did recommend several text books to her students, but the presentation of the material is what makes her approach to Math "living".
Below are several of the resources that I have used and loved, and some that are on our list as our children get older...
Living Math: A Guided Journey (book + DVD - get both, trust me!) This set is not actual curriculum, but the why and how of implementing CM's methods for teaching Mathematics.
This is a MUST have if you want to truly and purely implement "living" math into your curriculum and there is no other product out there that so thoroughly explains the method.
Also, make sure to join the Charlotte Mason Math Together facebook page. They are the most patient and helpful CM-specific group when it comes to adopting Mason's approach to living math.
The above listed is to teach the teacher about the CM method.
However, when you're ready to dive in at the Elementary level, then you'll defintely want to check out The Charlotte Mason Elementary Arithmetic Series. It's the only pure Mason math curricula available right now - meaning that you don't have to adapt or wonder if everything is covered in the prescribed order. Richelle Baburina, the author, has crafted a beautiful math book that is suitable for 1st grade (Form 1b) but it's wonderful to use to find any gaps that your children may have so that they don't progress having never really grasped certain concepts.
At this point (spring of 2018) there is only book 1 available, but future levels are slated to be released soon, so keep checking back.
HOWEVER, in the mean time, if you have older students, there are still other excellent resources available that are compatible with the CM method of teaching math. Within the CM homeschooling community, you'll often find families using the following programs with great success:
Strayer-Upton Math Books #1-3
Jacob's Elementary Algebra
Jacob's Geometry
Stay tuned for updates and check back as I continually add to my list!
If you have a recommendation, please contact me so I can check it out!