You would measure it in litres
since you're probably talking about the volume of water in the bucket, you could use either ml or liters (1 liter is 1000 ml), grams are a measure of weight and meters measure length.
litre
A millimeter is a measure of distance (length) A milliliter (different word) is a measure of volume. One liter is 1000 milliliters, so 6.7 liters would be 6,700 ml.
9
Is this a trick question? If you have a narrow bucket that holds 60 liters than it would seem very tall but if you have a wide flat bucket that holds 60 liters, it would be a different height or how wide.
328 ML = 328,000,000 liters (ML would imply 10^6 liters and mL would imply 10^-3 liters)
Multiply liters by 1,000 to get ml
A ruler
You could fill the 7-liter bucket and pour water into the aquarium until it is full, but that would make too much sense. If you really need to have three liters, fill the 7-liter bucket (which, although unmarked, will be larger than the 4-liter bucket) and pour it into the 4-liter bucket. When the 4-liter bucket is full, there will be three liters remaining in the 7-liter bucket.
Milliliters - pots of yogurt don't normally come in liter sized containers. You measure yogurt in ml and milk in l. You can also measure it in grams.
350 liters = 92.46 US gallons = 76.99 imperial gallons