Answer :
I tried to think of a fancy formula for it, then decided it's just easier to list them:
1
2
3
11
12
13
21
22
23
That's 9 of them.
1
2
3
11
12
13
21
22
23
That's 9 of them.
there are 9 numbers that are positive integers that can be formed by the #s 1,2,&3 THAT R LESS THAN 25
1
2
3
11
12
13
21
22
23