Jack's birthday is in 4 weeks. How many days is it until Jack's birthday? describe how you could use a number line to solve.

To determine how many days is it until Jack's birthday, we need a conversion factor to convert from weeks to days. We know, as a fact, that in one week there will be 7 days. So, we use this value. We do as follows:

4 weeks (7 days / 1 week) = 28 days until Jack's day