Answer:
20
Explanation:
4, 5, 1,8 and 2.
If we count them we have 5 numbers.
Then we want to form two-digit numbers without repetition.
There are 5 numbers possible to occupy the first digit, 4, 5, 1, 8 and 2.
Because it’s without repetition, the number that filled the first digit cannot be the second digit.
So the number possible to occupy second place is 4 different numbers. (5-4)
So there are 5 x 4 = 20 numbers that can we form from those 5 numbers: 4, 5, 1,8 and 2 without repetition.
