In the following arrangement of numbers, investigate the sum of all the numbers in a row. State your rule. Then use the rule to find the sum of the numbers in the 30th row.

(Source: Mathematics Teaching in the Middle School, Nov-Dec 1997)
In the given arrangement of numbers, investigate the sum of all the numbers in a row.
In the following arrangement of numbers, investigate the sum of all the numbers in a row. State your rule. Then use the rule to find the sum of the numbers in the 30th row.

(Source: Mathematics Teaching in the Middle School, Nov-Dec 1997)