Summary

Groups with an even number of objects can be separated into two equal parts, or halves.

For some numbers, you can continue taking half until you reach the number 1. These numbers are called super-even numbers.

You can use pairing to show that:

the sum of two odd numbers is even,
the sum of two even numbers is even,
the sum of an odd number and an even number is odd.

Zero is an even number.

A tournament is organized for a super-even number of players. If the number of players is not super-even, you can make it that way by asking for more players or restricting the number who play. Which of the two ways would you try to work out for weach of the following and why?