# 2.10: Exercises

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Exercise $$\PageIndex{1}$$

Repeating my advice from the previous chapter, whenever you learn a new feature, you should try it out in interactive mode and make errors on purpose to see what goes wrong.

• We’ve seen that n = 42 is legal. What about 42 = n?
• How about x = y = 1?
• In some languages every statement ends with a semi-colon, ;. What happens if you put a semi-colon at the end of a Python statement?
• What if you put a period at the end of a statement?
• In math notation you can multiply x and y like this: x y. What happens if you try that in Python?

Exercise $$\PageIndex{2}$$

Practice using the Python interpreter as a calculator:

1. The volume of a sphere with radius $$r$$ is $$4/3 \pi r^3$$. What is the volume of a sphere with radius 5?
2. Suppose the cover price of a book is $24.95, but bookstores get a 40% discount. Shipping costs$3 for the first copy and 75 cents for each additional copy. What is the total wholesale cost for 60 copies?
3. If I leave my house at 6:52 am and run 1 mile at an easy pace (8:15 per mile), then 3 miles at tempo (7:12 per mile) and 1 mile at easy pace again, what time do I get home for breakfast?

This page titled 2.10: Exercises is shared under a CC BY-NC 3.0 license and was authored, remixed, and/or curated by Allen B. Downey (Green Tea Press) .