Only sentences 1 and 3 require a revision which is bolded in the underlined corrected sentences.
1. The winning lottery numbers are three, fifteen, nineteen, and twenty seven.
This sentence needs a revision. There should be a hyphen between twenty and seven. Compound numbers, numbers that consist of two words, should always be hyphenated.
Therefore, the sentence should be:
<u>The winning lottery numbers are three, fifteen, nineteen, and</u><u> twenty-seven</u><u>. </u>
2. At least one-fourth of the paintings—which are all by American artists—will be included in the special exhibit.
This sentence is okay as is. An em-dash, the long dash, can be used in place of commas. It has essentially the same effect.
3. Mr. Singh, an accomplished musician, plays three instruments: piano, trumpet and clarinet.
This sentence is technically okay as it is, but it is probably more accepted to use the oxford comma (the comma before the and). Remember, that a colon can be used after a complete sentence, not after a sentence fragment. It is helpful to use it before a list of three or more things.
Therefore, the sentence should be:
<u>Mr. Singh, an accomplished musician, plays three instruments: piano, </u><u>trumpet, and clarinet.</u>
