Answer:
<em>
of Steph's annual income is from her full-time job.</em>
Step-by-step explanation:
Suppose, Steph's annual income is 
Given that, 80% of Steph's annual income is from her full-time job.
So, <u>the amount of income from her full time job will be</u>: 
Now, for finding the income from her full time job as a fraction of Steph's annual income, we just <u>need to divide "income from full time job" by "total annual income"</u>.
So, the fraction will be: 
That means,
of Steph's annual income is from her full-time job.