Page 49 - October 2021

Subject: Mathematics
Topic: Sieve of Eratosthenes
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Date: 1 October 2021
Activity: Hands-on activity to teach prime numbers and composite numbers
Sieve of Eratosthenes is a method of finding the prime numbers from 1 to 100 which was
invented by a Greek Mathematician Eratosthenes. The students learnt to follow the same steps
and found the prime numbers from 1 to 100.
Method: They were asked to draw a grid of numbers from 1 to 100 and cross out 1 as it is
neither a prime number nor a composite number. Later, they started crossing out all the
multiples of 2, 3, 5 and 7 and encircled all the remaining numbers. These encircled numbers
were the prime numbers. The children enjoyed the activity.