Answer:
Step-by-step explanation:
6 7 8 is one possibility
789 is another choice.
123 even works.
So how many numbers are there like this?
You can't have 0 in the 100s place and you can't have 8 0r 9
So there are 7 numbers 1 2 3 4 5 6 7 possible choices for the hundreds.
You can't 0 in the tens place nor 1 nor 9
You can't have 0 or 1 or 2 in the units place
In all I think you could write 84 such numbers.
