Every weekday comes back after 7 days.
If today is Monday, in 7 days it is Monday again - and in 14 days too.
For the rest you just keep counting - 9 days is 7 + 2, so 2 days after today's weekday.
Example
- Wednesday
For parents
What does this exercise practice?
Weekday puzzles practice the calendar's rule of seven (modular counting without a formula) and reinforce the order of weekdays - the child discovers the rhythm themselves instead of memorizing it.
Common pitfalls
Without the rule of seven, the child counts through every single day, which gets error-prone with bigger jumps. It helps to subtract full weeks first (with 9 days, one week leaves 2), then just count on the remainder.
How to practice at home
Look at a calendar together and try it out - which weekday is it in one week? In two weeks? Then count on a few more days.