James gets 80 emails a day.  20% of those emails don't require any response.  He responds to the rest of them.  How many emails does he respond to in a 5 day work week?
He gets 80*.2=
<gadget id="calculator">80*.2</gadget>
<output>16</output>
16 emails he doesn't need to respond to.
So he responds to 80-16=
<gadget id="calculator">80-16</gadget>
<output>64</output>
64 emails.
So he responds to 64*5=
<gadget id="calculator">64*5</gadget>
<output>320</output>
320 emails a week.

<result>320</result>