Please indicate if the following statements are true or false according to the text.

1. The passage mainly talks about the reasons why some elementary computing patterns were not developed until the fifteenth century.
True False

2. The author believes that mental difficulties were a central reason for the late development of some elementary computing patterns.
True False

3. Calculations with grouping systems involve memorizing numerical combinations.
True False

4. Using a ciphered numeral system does not require any memorization.
True False

5. The unavailability of cheap paper and other writing materials such as pens was a reason for the slow development of arithmetic systems.
True False

6. The paper we use today was developed much later than rag paper.
True False

7. Rag paper was probably expensive because its manufacture required human labor.
True False