
Identify
if a number is prime or composite.
Type any number in the control box below and hit
Enter, then you can change the value of the number by using
the up and down triangles.
You
will be shown if this number is prime or composite. If it is composite,
you will also be shown which number you can divide it by, apart from 1.
The
largest number you can type is 10.000.000.000

Investigate:

From number 2, using the up triangle, go up one at the time and count
the prime numbers in the first hundred: from 2 to 101.
 Now type a number of 9 digits, start with one
ending in 00, go up one at the time and count the prime numbers in this
hundred.
 What can you deduce from this?
