hi... My kid start learning while she is 4 months old. and now she is 2 years old. I began the domain method while I am using the black and white card and later part I add in the shichida method. You will find both of them you need to use it at different stage. Sometime changing of method of using the flash card is a necessary step
....as your kid will not get bored on the teaching skill of you. I have specify the learning and teaching skill in my blog. And I have post more detail on how I teach my kid. Kindly take a look... and I hope it is helpful for you
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http://littlemommy2012.blogspot.com/