My 13 year old just can't memorize timetables?

She confessed she really didn't know them cause she has finals, So i said "Sure I will help you". I have tried and tried she just cannot memorize them. I am not sure if this is a disability or what i already knew her memory wasn't outstanding, Do you think this is a condition? Do you have any techniques that might work? She needs help with grammar also. Tutor is kinda out of thee question.