in order to calculate the gross profit$ would i multiply the units sold by unit sales$ and substract the unit cost once?

10*2.3-0.67=gross profit

or

(10*2.3)-(10*0.67)

since 0.67 is the cost for just ine unit?

and how would i calculate the gp%?

unit sold 10 unit sales & unit cost # 0.67 Gross profit GP% ? 2.3