What are some occupations that involve math from Chapters 6 through 10 of The Giver?

Occupations requiring use of math are Instructor, Engineer, and Doctor. 

A community cannot function without math.  Math is required to design buildings, distribute supplies, and for all aspects of technology.  We know that technology is important in Jonas's community, and we can assume that high level math is as well.

The Instructor of Elevens is one occupation that requires math.  One of the reasons we can tell this is because the calculator is so...

Occupations requiring use of math are Instructor, Engineer, and Doctor. 

A community cannot function without math.  Math is required to design buildings, distribute supplies, and for all aspects of technology.  We know that technology is important in Jonas's community, and we can assume that high level math is as well.

The Instructor of Elevens is one occupation that requires math.  One of the reasons we can tell this is because the calculator is so important to Elevens that they actually have special clothing for it.  The boys are given trousers “with a specially shaped pocket for the small calculator that they would use this year in school” (Ch. 6).  It does not say where the girls keep their calculators.  Nonetheless, someone has to teach them how to use them. 

Another occupation that requires math is Engineer.  While waiting for the ceremony to begin, Asher shares a story about a supposed former Eleven’s assignment. 

"I heard about a guy who was absolutely certain he was going to be assigned Engineer," Asher muttered as they ate, "and instead they gave him Sanitation Laborer. He went out the next day, jumped into the river, swam across, and joined the next community he came to. Nobody ever saw him again." (Ch. 6) 

Jonas tells him it is just a story, but you can see how children would be frightened by it.  An Eleven with an affinity for math might expect to be an Engineer, and would be disappointed to end up with a less prestigious occupation like Sanitation Laborer.  Engineer is probably a very valued job, requiring mathematical ability. 

During the ceremony, a few other assignments are mentioned that require math, including Doctor and, once again, Engineer. 

Jonas knew that each one was thinking about the training that lay ahead. For some--one studious male had been selected as Doctor, a female as Engineer, and another for Law and Justice--it would be years of hard work and study. (Ch. 7) 

There are likely other occupations that require the use of math.  It is hard to tell, because we are not told what all of the assignments are.  Many jobs require math, in small ways or large ones.  For instance, Fiona might use math as a Caretaker of the Old if she has to determine medical doses or nutrition intake.