Hi babymum, we don't have CMA in our country but we do have a abacus school that Cammie attends to irregularly (we attended about 20 sessions the whole year). There are major differences between the two such as CMA uses two hands while SIP uses one-handed operation. In terms of ansan practice, I am very impressed with CMA because I haven't seen such speed in our school in the same age-group on your video.
To answer you question, yes soroban will tend to confuse a child IF he has a weak math foundation. The initial trouble we had when transitioning from soroban to Singapore Math is the order of which numbers to add/subtract first. Other than that, it is very similar because of the use of Singapore's grouping by ten method and soroban's bonds of 10.
Honestly, I think soroban could be a great stand-alone math instruction for the basic operations provided that each finger movement is explained and totally understood by the student first. For example, we "shoot-up 7" when adding 7 to 6 because the formula is for adding 7 is -3,+10. Shooting up 7 (moving heaven bead 5 and 2 earth-beads upwards) means lessing 5 while adding 2, which is actually lessing 3. Sorry if this is vague!
Cammie is not receiving mental math instruction yet at SIP but it's a different story at home. I make her solve every question in her school books in ansan (mental math). Regarding her speed, I would say not bad because on her best mood, she is at par with Xavier (brother of Cherlyn Lee, one of the girls on your video) who also attends CMA. So it's not about the school but as all things EL, about practice.
Digg
