+0  
 
0
61
2
avatar

How many four-digit numbers do not contain the digit 1 or 2?

 Jul 21, 2020
 #1
avatar
0

My computer says there are 3584 [Thanks geno3141 - I only counted the first 3000!!!] 4-digit numbers that have no 1 or 2 in them. In other words, they must start with:

 

3000  3003  3004  3005  3006  3007  3008  3009  3033  3034.......etc. and end with .....  9993  9994  9995  9996  9997  9998  9999  Total =  3584 such numbers.

 Jul 21, 2020
edited by Guest  Jul 22, 2020
 #2
avatar+21953 
0

There are 7 choices for the first digit:  3, 4, 5, 6, 7, 8, and 9; only 0, 1, and 2 are not acceptable.

 

After the first digit, there are 8 choices for the second, third, and fourth digits (only 1 and 2 are not acceptable).

 

This means that there are  7 x 8 x 8 x 8  =  3584  possibilities.

 Jul 21, 2020

59 Online Users

avatar
avatar