Q. I am editing some reports for my college. I had some good times in the ’60s, was educated in the ’70s, worked in the ’80s and ’90s, but the ’00s confuse me. What do we call them?

Q. If numbers must be written out by using words, are commas added in the same places as they would be used for digits? Example: 23,504,070; twenty-three million, five hundred four thousand, seventy. Thanks!

Q. In prose, when writing percentages, which is correct: 10 percent; ten percent, or 10%?

Q. Our company has always presented costs to clients in both written and numerical form. For example, “The cost for our services is two thousand one hundred fifty dollars ($2,150).” One client has pointed out that the number in parentheses is negative and therefore we owe him money. How can we present numbers to clients in both written and numerical form without using the parentheses, which may indicate a negative number?

Q. When hours and minutes are mixed in a sentence that is describing a duration, are all numerals used? For instance, is it “The spacewalk lasted 7 hours and 54 minutes” or “The spacewalk lasted seven hours and 54 minutes”?

Q. I’m editing the autobiography of a delightful, elderly R&B songwriter who writes of his song reaching “#3” on the Billboard chart, but later writes of having a “top ten” hit. Are there special rules for documenting music charting, or should we spell out all numerical positions to be consistent with CMOS? In some paragraphs, he lists the many chart positions reached by his songs, so spelling out makes the section difficult to read. I don’t want to hurt his feelings by telling him that we should just summarize his chart-topping accomplishments or put them in an appendix. Egad—am I too tenderhearted to be an editor?

Q. How does a person write out ninety-two thousand, fifty-five dollars in numeral form? I should know this, but I’m stumped.

Q. This has to do with page ranges for a bibliography, as described in CMOS. It is clear that 125–29 is correct and 125–129 is not. However, it is not clear what to do with a range like 145–155. Should it be 145–55 or 145–155? The trouble comes from the part of the explanation that reads “use two or more digits as needed” and the lack of examples to address this particular situation. I would think 145–55 is sufficient, but then, I don’t trust my own intuition because 125–9 seems sufficient to me, too. And that is wrong. Please help!

Q. I have been under the impression that extensions on a date (st, nd , rd, etc.) are proper when used simply with a month (January 15th) but are not used in connection with a year (January 15, 2009). Please advise if this is correct or provide instruction to the contrary.

Q. In expressing the statistical change in GDP figures over the course of multiple decades, would it be most correct to write “2000% increase,” “2,000% increase,” or “2,000 percent increase”? Our copyeditor favors the second option, but the use of the comma in that context just doesn’t sit right with me. Please advise.