In regards to Math--I have a 12 month old and I am beginning to teach him steps 1-5 of the 10 step matrix. Do I expect instant results? Of course not. But it's really just familiarization and pre-loading now.
If you already plan to begin the program at 2 years old when it's "recommended," then there is really nothing to lose by starting early, and just focus on input, input, input. I am realizing that this program can be introduced as soon as you start flashing cards in general. In this case, just add in the JG matrix cards too.
There are a few things you can to to begin the program "early," you can practice the recommended counting forwards and backwards (steps 1 & 3) (I would do it all the way through musically with a song at every diaper change, alternating with the ABC song, or every time you go up and down the stairs).
I would also start flashing the JG matrix #'s alongside your LM or whatever dot math program you use if you use one. Either by hand, or scanning and using LR. (If you don't do "doman" dots already, I would start doing that too. There are powerpoint slides for download so you can do it for free if you don't have LM). I would also physically reinforce the flashcards with cardboard, do a little copying, glueing, and laminating. Copy the flashcards, color each numeral one standard color, and sandwich thin cereal-box type cardboard in between and then laminate. Your baby is do young, they won't get completely mangled in an instant this way, I personally will never let baby touch my originals (this is only for personal use of course.) Because the Doman dots and the matrix dots are both 1=1 in terms of quantity, they do not conflict with each other at all.
When the time comes, your child will be ready to manually place the dots themselves and learn addition and subtraction more quickly b/c you'll have done all this pre-loading & familiarization IMO. Or, if they do pick up the Doman Dot program easily, this will help them transition to numerals.
Go on amazon and get an alligator puppet. Start teaching that the alligator only eats the bigger pile of toys, or the flashcard with more dots.
I really love Meet the Numbers. I think it's a great program to use in conjunction with this to help solidify numeral recognition. Like I showed in a previous post, just color your JG flashcards to match the Meet the Numbers characters.
After coloring them, color copy or hand color a second set and put a number line on the floor with them, left to right to let baby see and crawl on. They sell this
http://www.staples.com/office/supplies/p1_Self-Laminating-Supplies_19313_Business_Supplies_10051_SC3:CG9:DP2148:CL142542 in 12 inch long rolls at walmart for $5.74 and it has not harmed my laminate floor, I recently pulled it up once to redo the colors. You can start with 0-9 with dots or go all the way to 20 using plain numbers with no dots for # 10-20 but do use the correct colors. (so 11 would be the same color as 1, 12 would be the colors of 1 & 2, etc. I will post a pic of mine soon.)
I would also start showing this youtube clip by DadDude once a day or so.
http://www.youtube.com/v/2PUVVXZLIrY&rel=1It will take "longer" to work through the program in a sense, but by the time you get to the recommended age, baby should work through it *faster* by that point. I hope that made sense.
I got the program when my DD was 18 months and we started the familiarization process. I wish I had been more creative back then about ways to adapt it for the younger crowd. Really, it's never too early to start!