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Math challenge I-B Number theory homework

 
 
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Math challenge I-B Number theory homework
by Yuyu Wei - Thursday, 2 April 2020, 12:55 PM
 

Good afternoon!  I have a question  In Number Theor5.25. Between 20 and 60 is not mean contain 20 and 60?

 
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Re: Math challenge I-B Number theory homework
by Areteem Professor - Friday, 3 April 2020, 12:38 PM
 

Since the problem says "(strictly) between $20$ and $60$", the numbers $20$ and $60$ are not included.

When a statement like "between $a$ and $b$" can be ambiguous, we usually say "strictly between $a$ and $b$" or "between $a$ and $b$ (inclusive)" to distinguish the case where we do not include $a$ and $b$, and when we include $a$ and $b$.

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Re: Math challenge I-B Number theory homework
by Yuyu Wei - Friday, 3 April 2020, 6:20 PM
 

Thank you ! I got it.