Answer:
By "small numbers" you probably mean exponents. The exponent just represents how many times you multiply the number by itself. For example,
means 4 x 4 x 4, which equals 64.
The "letters" are called variables. They represent an unknown value. The most common variables you'll see are x and y, which are used a lot in graphing. Variables are often used in equations. For example:
"Maria wants to buy cupcakes, at $2.50 each. She only has 10 dollars. How many cupcakes can she buy?"
You would use an exponent to solve this problem. If you make cupcakes "C" then you can say:
C (the # of cupcakes) times 2.50 (cost per cupcake) = 10.
(in shorter terms, 2.50c=10.)
You can then solve for "c" by dividing by 2.50 on both sides and you can then see that Maria has enough money to buy 4 cupcakes.
Hope this helps! :)