# How Many Different Numbers of Six Digits Each Can Be Formed from the Digits 4, 5, 6, 7, 8, 9 When Repetition of Digits is Not Allowed? - Mathematics

How many different numbers of six digits each can be formed from the digits 4, 5, 6, 7, 8, 9 when repetition of digits is not allowed?

#### Solution

Number of ways of filling the first digit = 6
Number of ways of filling the second digit = 5
(as repetition is not allowed)
Number of ways of filling the third digit = 4
Number of ways of filling the fourth digit =3
Number of ways of filling the fifth digit = 2
Number of ways of filling the sixth digit = 1
Total numbers = 6xx5xx4xx3xx2xx1=720

Concept: Combination
Is there an error in this question or solution?

#### APPEARS IN

RD Sharma Class 11 Mathematics Textbook
Chapter 16 Permutations
Exercise 16.2 | Q 26 | Page 15