The Sieve
of Erathostenes is a procedure to find the first prime numbers.

Draw a table with the natural numbers starting with 2. This table is usually
filled with the first hundred natural numbers, but here it only goes up
to the number 46.
 Start
with the number 2, leave it, but from there, count by twos and drag out
the numbers that are multiples of 2.
 The
first of the remaining numbers is 3, leave it and from 3, drag out
all the numbers that are multiples of 3.
 The
next of the remaining numbers is 5, leave it and from 5, drag out the
numbers thar are multiples of 5.
 Go on and
every time you get to a number that has not been dragged out, leave it, but from there,
drag out all the numbers that are multiples of it. Continue, right
to the end.
 Finally,
only prime numbers are left.
