Finding prime numbers by sifting


A prime is a number greater than 1 that cannot be formed by multiplying two smaller whole numbers. In other words, a prime can be divided into whole numbers only by itself and the number 1. For example, 5 is a prime because no numbers can be divided into it except for itself and 1. However, 6 is not a prime since it can be divided by 2 and 3. The ancient Greek mathematician Eratosthenes discovered a simple way to find all small primes using a “sieve” system. It does so by iteratively marking as composite (i.e., not prime) the multiples of each prime, starting with the first prime number 2. This worksheet provides a number table from 1 to 100 that kids can use to find primes by applying the sifting algorithm of Eratosthenes.

A fruity challenge using simple algebra

A fruity challenge using simple algebra

All about the number 3

All about the number 3

Counting From Six to Ten by Finger Gestures

Counting From Six to Ten by Finger Gestures

Addition Table 10 by 10

Addition Table 10 by 10

Multiples Shown on Hundreds Charts

Multiples Shown on Hundreds Charts

Multiplication Table 12 by 12

Multiplication Table 12 by 12

Addition Table 12 by 12

Addition Table 12 by 12

Addition Table 9 by 9

Addition Table 9 by 9

Counting From One to Ten by Finger Gestures

Counting From One to Ten by Finger Gestures

Chinese Multiplication Table 9 by 9

Chinese Multiplication Table 9 by 9

Counting from one to nine one by one via incrementation

Counting from one to nine one by one via incrementation

Multiplication Table 10 by 10

Multiplication Table 10 by 10

Counting From One to Five by Finger Gestures

Counting From One to Five by Finger Gestures

Colored Table Chart of Numbers From One to Hundred

Colored Table Chart of Numbers From One to Hundred

Exercises for counting to ten

Exercises for counting to ten

Colored Table Chart of Numbers From One to Fifty

Colored Table Chart of Numbers From One to Fifty

Exercises for counting to nine

Exercises for counting to nine

Exercises for counting to five

Exercises for counting to five

Exercises for counting to three

Exercises for counting to three

Say Numbers From Zero to Billion in English

Say Numbers From Zero to Billion in English

Numbers From One to Thirty

Numbers From One to Thirty

Numbers From One To Twenty

Numbers From One To Twenty

Numbers From One To Ten

Numbers From One To Ten

Numbers From Eleven To Twenty

Numbers From Eleven To Twenty