Negative numbers

Hi Emile,
So far your work in class can be successfully described using negative numbers. For instance, last week out of 8 assigned geometry exercises, you solved: at home 4, and in class -4 more than at home; so it remains to solve ?? exercises.
Your next algebra assignment is, after reading Section 13 "Addition of negative numbers," to compose 5 word problems whose solution would be given by:
(1) addition of a positive and a negative number,
(2) addition of two negative numbers,
(3) subtraction a positive number from a negative one,
(4) subtraction of a negative number from a positive one, and
(5) subtraction of a negative number from a negative one.
In the book, there are examples of such problems involving temperatures and annihilation of elementary particles. I'd like you to compose problems about years of life of ancient Greek geometers, as written on p. viii of Kiselev's Geometry / Book I.
After finishing this assignment, you are allowed to torture your teacher and classmates by asking them to solve your problems.