KS2 Primary Maths Age 9-13 - Number and Place Value: Prime Numbers - Explained

The video tutorial explains how to identify prime numbers, using 89, 95, and 87 as examples. It highlights that 89 is prime because it has only two factors: one and itself. The video further explains that 95 is not prime as it ends in 5, making it divisible by 5, and 87 is not prime because it is divisible by 3. The tutorial emphasizes the importance of understanding why numbers are not prime to gain full marks in exams.

Which of the following numbers is a prime number?

• 87

• 89

• 95

• 100

What makes a number a prime number?

• It has more than two factors.

• It is an even number.

• It has exactly two distinct factors: 1 and itself.

• It is divisible by 5.

Why is 95 not considered a prime number?

• It is a perfect square.

• It is less than 100.

• It is an even number.

• It ends in 5 and is divisible by 5.

Which number is divisible by 3, making it not a prime number?

• 97

• 87

• 95

• 89

How can you determine if 87 is not a prime number?

• Check if it ends in 0.

• Check if it is divisible by 2.

• Check if it is divisible by 3.

• Check if it is a perfect square.