That must have been quite a grade school that taught you that “under the law in effect between 1952 and 1986 — Cruz was born in 1970 — someone must have a citizen parent who resided in the United States for at least 10 years, including five after the age of 14, in order to be considered a natural-born citizen. Cruz’s mother, Eleanor Darragh, was born in Delaware, lived most of her life in the United States, and gave birth to little Rafael Edward Cruz in her 30s.”
Not hard to understand at all. So simple even a fifth or sixth grader can understand it.
It's all the exceptions people come up with that are hard to understand, like your example as written in your post, for instance.