Complex sentence: As a child, Fleming had a keen interest in statistics, and so at the age of 9, when he began learning the game of pocket billiards, he made detailed records of his runs, how much he played, and his practice time.
Split into simpler sentences: As a child, Fleming had a keen interest in statistics. At the age of 9, when he began learning the game of pocket billiards, he made detailed records of his runs, how much he played, and his practice time.