Year 5 Multiplication and Division – Prime digits

Establish whether a number up to 100 is prime and recall prime numbers to 19

Prime digits printable sheet (PDF)

 

Investigation: Prime digits

 

 

 

Mike has written down all of the prime numbers between 1 and 100.


Can you work out which digit he writes the most and which he writes the least?

 

Why do you think these digits are used the most and the least?


Answer

The least used digit is 0 which isn’t used. 6 and 8 are used twice (61 and 67; 83 and 89)

The most used digits are 1 and 3

1 – 11, 13, 17, 19, 31, 41, 61, 71
3 – 3, 13, 23, 31, 37, 43, 53, 83. 

The understanding of odd and even, use of the digit in each times table (e.g. x5) give a reason as to why they are used the most/least.