Question

How many 4 digit numbers, in all are there ?

• A. $9999$
• B. $9990$
• C. $9000$
• D. $8999$

Answer 1

The correct option is C $9000$

$\Rightarrow$ The smallest $4-$digit number $=1000.$

$\Rightarrow$ The greatest $4-$digit number $=9999.$

$\Rightarrow$ Total $4-$ digit numbers $=(9999-1000)+1$

$=8999+1$

$=9000$

So, we say that we have $9000$ four-digit numbers.