Carl Sandburg (6 January 1878 – 22 July 1967 / Illinois)

Arithmetic is where numbers fly like pigeons in and out of your
    head.
Arithmet ic tell you how many you lose or win if you know how
    many you had before you lost or won.
Arithmetic is seven eleven all good children go to heaven -- or five
    six bundle of sticks.
Arithmetic is numbers you squeeze from your head to your hand
    to your pencil to your paper till you get the answer.
Arithmetic is where the answer is right and everything is nice and
    you can look out of the window and see the blue sky -- or the
    answer is wrong and you have to start all over and try again
    and see how it comes out this time.
If you take a number and double it and double it again and then
    double it a few more times, the number gets bigger and bigger
    and goes higher and higher and only arithmetic can tell you
    what the number is when you decide to quit doubling.
Arithmetic is where you have to multiply -- and you carry the
    multiplication table in your head and hope you won't lose it.
If you have two animal crackers, one good and one bad, and you
    eat one and a striped zebra with streaks all over him eats the
    other, how many animal crackers will you have if somebody
    offers you five six seven and you say No no no and you say
    Nay nay nay and you say Nix nix nix?
If you ask your mother for one fried egg for breakfast and she
    gives you two fried eggs and you eat both of them, who is
    better in arithmetic, you or your mother?