Congratulations. You got the buffalo onboard without a stampede. But before you can take off, the air traffic control tower needs to know how much your plane weighs, and how much your four-legged cargo weighs, too.
	Your 747 owner's manual says the plane weighs about 500,000 pounds. But air traffic control needs to know the weight in tons. To convert pounds into tons, you'll need to know about units of weight.