number of digits
= 3x2x1
= 6 , we could actually list them
137
173
317
371
713
731
Here is a list of primes:
http://primos.mat.br/indexen.html
you will find that all are prime except
371, 713 and 731
731 =17 x 43
713 = 23 x 31
371 = 7 x 53
A) How many of the three digit numbers can be made from all of the digits, 1,3 and 7, and used only one each,are prime?
B) What about 2,3 and 4?
Once I get to know what the answer to the first one is, I'll figure out the second one myself.And then if I tell you what I got for the second part (b), can you please tell me if it's correct then?
2 answers
1+1=11
1 answer