Final answer:
To calculate the average atomic mass of an element from percent abundances, convert the abundances to decimals, multiply each decimal by the atomic mass of the corresponding isotope, and sum the products.
Step-by-step explanation:
The average atomic mass of an element can be calculated using the percent abundances of its isotopes. To do this, convert the percent abundances into decimal form by dividing by 100. Then, multiply each decimal abundance by the respective isotope's atomic mass. Finally, add the products together to get the average atomic mass of the element.