The Ten Commandments of Mathematics

While I was rearranging my books and papers, I happened to come across this sheet of paper with the Ten Commandments of Mathematics written down. I thought this may interest others too. So here they are:

1. Thou shalt not divide by zero;

2. Thou shalt not multiply any inequality by zero;

3. Thou shalt not mix up different values of a multiple valued function;

4. Thou shalt not invert the order of operations unless inversion is valid;

5. Thou shalt not proceed to determine a quantity unless thou hast established its existence;

6. Thou shalt not generalise from particular cases;

7. Thou shalt not employ divergent series and divergent integrals;

8. Thou shalt not believe by seeing;

9. Thou shalt not depend on intuition alone; and

10. Thou shalt not mix-up the two-way implication and the two one-way implications.

Hope you find these useful!