Finding mass based on amu and % abundance

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To find the average atomic mass of oxygen, the contributions of each isotope based on their atomic mass units (amu) and percent abundance must be calculated. The isotopes are Oxygen-16 (15.995 amu, 99.759% abundance), Oxygen-17 (16.995 amu, 0.037% abundance), and Oxygen-18 (17.999 amu, 0.204% abundance). The correct formula involves multiplying each isotope's mass by its decimal abundance and summing these values. A common mistake is not converting the percent abundance into decimal form before performing the calculations. The average atomic mass of oxygen can be accurately calculated using the formula provided.
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Homework Statement



Oxygen has 3 isotopes. Oxygen-16 has the amu of 15.995 and its natural percent abundance is 99.759. Oxygen-17 has a mass of 16.995 amu and its natural percent abundance is 0.037. Oxygen-18 has a mass of 17.999 amu and its natural percent abundance is 0.204. What is the average atomic mass of oxygen?

Homework Equations



I think I forgot these...

The Attempt at a Solution



I couldn't remember what the process is supposed to look like to figure this sort of problem out, so I tried to multiply the mass by the percent abundance, but the answers made very little sense. If somebody could help me figure out where I messed up, PLEASE RESPOND!
 
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The average atomic mass of an element is much like a simple mixture problem that you learn in first year Algebra such that you can resort directly to percentage contributions formula.

AverageAMU = 0.99759*16 + 0.00037*17 + 0.00204*18
 
Thank you so much!
 
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