Answer:
you can use math way it will be on there
it means 3 and then "e" means is up of the 3so its 3↖-6
Since we are trying to find the number of sequences can be made <em>without repetition</em>, we are going to use a combination.
The formula for combinations is:

is the total number of elements in the set
is the number of those elements you are desiring
Since there are 10 total digits,
in this scenario. Since we are choosing 6 digits of the 10 for our sequence,
in this scenario. Thus, we are trying to find
. This can be found as shown:

There are 210 total combinations.
A = 1/2 h(b + x)
2a = h(b + x)
2a/h = b + x
x = 2a/h - b