Permutations and combination question How many arrangements of four digit numbers can be made using the numbers 2 through 9 if no numbers can be repeated?

a) 840

b) 504

c) 1680

d) 4096

Step-by-step explanation:

2,3,4,5,6,7,8,9 = 8 números diferentes

a

step-by-step explanation:

when a number is between two straight lines it means the absolute value.

to find absolute value you need to know how many numbers is that number away from 0.

when finding absolute value the number will always come out positive

so absolute value of -3 is 3

absolute value of 3/2 is 3/2

absolute value of -2 is 2

absolute value of 3.5 is 3.5

absolute value of -1 is 1

now put these numbers in order:

a)   |-1|, |3/2|, |-2|, |-3|, |3.5|