What is teamwork? Teamwork is helping each other to reach your own personal goal with almost anything in life. Whether that is in a team sport, school project or at work.
Team work is very important of a number of sports. In a game of netball where you cannot walk while holding the ball and where you cannot pass to yourself, you need more people there for you to pass to.
If there are two people and they both have one apple, and they swap apples then they still only have one apple. But if there are two people and they both have one idea, and they exchange ideas then they both have two ideas!