Here is another one:

1) A liter of water is one kilogram by definition.
2) One kilogram is 2.2 pounds.
3) A quart is 2 pounds.

4) Hence, a liter is 1.1 quarts.

Conversion charts say that a liter is 1.0566882607957349 quarts. Why
the difference?









The above includes many approximations. The real values are.

1) A liter of water is one kilogram by definition at 4C and 1 atmosphere
of pressure. But at 20C a liter of water is 0.9982 kilograms.
2) One kilogram is 2.2046 pounds.
3) A quart is 2 pounds approximately. Actually at 4C a quart of water
is 2.086 pounds. At 20C a quart of water is 2.082 pounds.

4) Hence, at 4C a liter is 1.0567 quarts and at 20C a liter is 1.0567
quarts. So the common measures we take for granted are about 5 % off.