A hundred watches have three laws:

1, each row has 10 numbers, and 10 rows (each column has 10 numbers and 10 columns).

2. The number on the right of two adjacent numbers in a row is larger than the number on the left 1.

3. The number below two adjacent numbers in the column is greater than the number above 10.

There are usually hundreds of tables in the textbooks of the first grade of primary school (learning factors and multiples, prime numbers (prime numbers) and composite numbers are also useful in the fifth grade), which is intended to let students know more clearly the arrangement order of numbers within 100 after they know the numbers within 100, which not only consolidates the numerical order of 100, but also can be used in tables.