Beanium Explore lab

What is the atomic mass of beanium? -- asked to learn how atomic mass is found.
To get the atomic mass of beanium, first each isotope was measured for its average mass, then we got its percentage, and then we did a calculation to get the atomic mass of the beanium. we did it in this way because that was the instructions of the lab.
Claim: The atomic mass of beanium is 0.4.
Evidence:

Bean Type	Number of Beans	Mass of Beans	Average Mass	Bean Percentage
Liminium	5	6.7	1.3	10%
Kidneum	15	7.7	0.5	30%
Peagen	30	6.7	0.2	60%

Reasoning:
((1.3[averagemass])(10[persentage])+(0.5[averagemass])(30[persentage])+(0.2[averagemass])(60[persentage]))/100 = 0.4