Answer as a mixed number = 5 & 1/3 gallons
That rounds up to 6 full gallons assuming s/he cannot buy a fractional amount of a gallon.
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Step-by-step explanation:
We multiply the two numbers given
8*(2/3) = 16/3
Then we can convert this to a mixed number if we wanted
16/3 = (15+1)/3 = 15/3 + 1/3 = 5 + 1/3 = 5 & 1/3
The teacher needs to buy 5 full gallons plus an additional 1/3 of a gallon of paint.
Assuming the teacher cannot buy a fractional amount of paint, s/he will need to bump that value to the nearest whole number. So the art teacher will need to buy 6 gallons of paint. He or she will have leftovers but it's better than coming up short.