There are 8 Ounces in a cup. Therefore the Tablespoon is 1/2 Ounce. A teaspoon is 1/3 of a tablespoon or 1/6 of an ounce. Remember this, 128 ounces in a gallon. 1/2 of a gallon is the next stop down = 64. 1/2 of that is a quart = 32 ounces. 1/2 of that is a pint = 16 ounces.
The difference between US Letter and Legal Paper sizes and international A4 is discussed here, however it is important to say that Letter is effectively the equivalent to A4 size in the USA.
Legal-size envelope. Lay the legal paper, printed side up, on a flat surface. Fold the bottom edge of the paper upward, creasing it across, 5 inches from the bottom. Use a ruler to make sure that the crease is exactly 5 inches from the bottom edge. This will leave the top 4 inches of the paper exposed.