I tutored some kids yesterday; it was fun. I can see some people whose blogs I read laughing.
Strange mixture of questions; one question how many different pizza combinations can be made from 7 toppings. Strange the four kids I was talking to had not heard of factorials and so their only method was by listing which I thought dumb. I was told this a topic that would be covered in May.
I was impressed that they came on a Saturday and were not required to come.
Anyway one of the questions intrigues me:
What number is 6 times its digit?
Now its easy to do by enumeration:
6 12 18 24 30 36 42 48 54 60 with 54 satisfying all properties:
5 + 4 = 9
9 * 6 = 54
BUT how to arrive at the solution without enumeration.
So far I have gotten as far as:
6 (a + b) = number
a + b = c
At this point I am stuck.