Write down the next line in the following pattern:
Our
Solution:
Each row describes the grouping of the digits in the line above.
The top row "1" has one one, so we write "11" for the
second row.
The second row "11" has two ones, so we write "21" for the
third row.
And so on.
To describe the line: 31131211131221
We say: one three, two...