There is a 9 gallon jug and a 5 gallon jug how can you get 7 gallons, there are no markers and it has to be precise

Is this homework?

Its just a riddle our teacher gives us after class for fun and we are stumped I know how to get it with a 5G and a 3G to get 4G but I can't get this one

1/2 of each jug equals 7 gallons.

But you don't know what half is, there are no markers and you have to be precise

1. Fill the 5-gallon jug, pour all of it into the 9-gallon jug
2. Fill the 5-gallon jug again and pour 4 gallons into the 9-gallon jug leaving 1 gallon in the 5-gallon jug
3. Pour 1 gallon into the 9-gallon jug
4. Fill up the 5-gallon jug and pour it all into the 9-gallon jug totalling 6 gallons in the 9-gallon jug
5. Fill up the 5-gallon jug again and pour 3 gallons into the 9 gallon jug leaving 2 gallons in the 5-gallon jug
6. Pour the 2 gallons into the 9-gallon jug
7. Fill up the 5 gallon jug
8. Pour the 5 gallons into the 9-gallon jug
9. 7 Gallons

BAM

NICE, thanks a lot appreciate it :)