Keke learned to calculate things right. 
"5 加5 等于几？" I showed my two hands to her.
"Ten" She said.
"5加1呢？" I showed one hand and one finger to her. 
Keke then heasitated and counted from one, two, three,.. till six.  I then turned out understood how she learned to count number, i.e., she can see and understand how many fingers are there, but she did not know what is the word that follows number "five", then she has to count from the right begainning to help her memorize that exact word.