[[x]] means that the integer should be rounded down to the greatest integer that is of the same value as x or is lower than x.
When converting English phrases into mathematical expressions/equations, we do things from left to right. That is why it's 4 - 20 instead of 20 - 4.
This rule is applied to division as well.
Answer:
28566.3
Step-by-step explanation:
98.3 + 28,468 = 28566.3