What is Pacific-Atlantic Rule for significant figures?

Answer 1

It's for determining the number of significant figures. Think of the U.S. in a map. The Atlantic Ocean is to the right. Pacific to left.

If a decimal is present, start counting from the "Pacific" (left).

If absent, count from "Atlantic" (right).

So, what are we counting? We count the first nonzero digit we encounter; and all subsequent digits.

E.G.: 432.30 gram has 5 sig figs.

6,000 has 1 sig fig.

Answer 2

The Pacific-Atlantic Rule states that when performing calculations with significant figures, you should always move from left to right just like crossing the Pacific Ocean to the Atlantic Ocean. Start calculating with the numbers on the left (Pacific) and end with the numbers on the right (Atlantic) to ensure that your final answer has the correct number of significant figures.