The number of days in w weeks is _________.
The number of days in w weeks is 7w.
We know:
\(1\ \text{week} = 7\ \text{days}\)
So for \(w\) weeks, multiply \(7\) by \(w\):
\(\text{number of days} = 7 \times w\)
Which is \(7w\ \text{days}\).
Quick check: If \(w = 3\), then days = \(7 \times 3 = 21\).