### Planet Plex Time

On Planet Plex, there are only 6 hours in the day. Can you answer these questions about how Arog the Alien spends his day?

### On What Day Did it Happen?

Read this article to find out the mathematical method for working out what day of the week each particular date fell on back as far as 1700.

### Calendars

Calendars were one of the earliest calculating devices developed by civilizations. Find out about the Mayan calendar in this article.

# How Many Days?

### Why do this problem?

For young children this problem is not as trivial as it first sounds. The difficulty in visualising or reciting the names of the months in order and how many days there are in each will probably lead to some sort of recording or need to look at a calendar or diary. At some point the discussion will involve deciding just what is meant by 'between'.

### Possible approach

It would be helpful if this coincided with work on sequencing the months of the year and learning the number of days in each month. Encourage children to discuss the question first in small groups and decide on what they think the answer might be. Then allow them to examine a Year 2000 calendar or a diary. Should they count the starting day and finishing day? Does knowing the starting day is a Friday and the finishing day is a Saturday help work out the answer? There is also the fact that February 2000, being a leap year, has 29 days, to discuss.

### Key questions

What does 'between' mean?
Should we count the starting and finishing days? Why?

### Possible extension

Once interpretations have been agreed upon, ask the children to pose their own similar questions for others to answer. What if the year was the current year? Could we work out the answer without going back to the beginning?

### Possible support

Large calendar pages that can be written on may be helpful. And discussion is always important!