Answer :

I don't think we will need to use a variable expression for this one.

3 weeks have 7 days, we know that. 

So, the numerical expression would be 3 x 7 = 21

3: weeks
7: days
21: days in 3 weeks.


Hope this helped
since there are 7 days in one week
so 3 weeks = 3 X 7 = 21 days
so, 21 is the answer.

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