The Numbers game comes with dot tiles for the numbers 1, 2, and 5 only. There are no dot tiles for the numbers 3, 4, 6, 7, 8, or 9. The use of dot tiles for the Numbers game is meant to introduce small children to the concept of counting, while making it fun for them. It's not meant to be an all-inclusive learning experience for each number.
Some additional context: the numbers 2 and 5 are important as they are 'skip counting' numbers. The number 2 also provides a quicker way to get to any even number, while the number 5 provides a quicker way (compared to 1 or 3) to get to odd numbers, and also to get to the number 10. Numbers 5 and 10 are both considered "benchmark" numbers as students learn to count.
One of the goals of the game is to help children figure out how to make bigger numbers out of small ones by combining the small ones in different ways. The missing dots add a fun challenge to the game.