Well, I am wrong. 7 and 13 are just prime numbers, not successive. 11 is prime too ... AS long as DS does not give me 17 instead of 18 for 2*9 ...
ANyway, it is still quite strange, since at the beginning of his learning, there was no problem with 7*2 and 2*7 being 14. It turns noww to be invariabily 13 since a month or so. It has probably something to do with dyslexia.

Last edited by raoulpetite; 04/15/12 07:20 AM.
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Sorry for the English !
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