Question

How many 4 – digit numbers are there in all?
A. 9999
B. 9990
C. 9000
D. 8999

Answer 1

HINT:- Let us first know about four digit numbers.FOUR – DIGIT NUMBERS are the numbers that have four digits, i.e. they have ones, tens, hundreds and thousands places.

Complete step by step answer:
The formula that we are going to use for solving this question is as follows:-
[(Greatest 4 – digit number) – (Smallest 4 – digit number)] + 1
In fact, to find the number of numbers between any two given numbers, we use the same formula.
The smallest four digit number = 1000
The greatest four digit number = 9999
Total four digit numbers = (9999 – 1000) + 1
                                                                        = 8999 + 1 = 9000
Therefore, there are 9000 four digit numbers in all.
Hence, the answer of this question is (c) 9000.
NOTE:-
To find the number of objects between two limits, that are the upper limit and the lower limit, we use the following formula:-
[(Upper limit) – (Lower limit)] + 1
Let us now find out the total number of three – digit numbers.
The smallest three digit number = 100
The greatest three digit number = 999
Total three digit numbers = (999 – 100) + 1
                                                                         = 899 + 1 = 900
So, the total number of three – digit numbers is 900.

Let us now find out the total number of 2 – digit numbers.
The smallest two – digit number = 10
The greatest two – digit number = 99
Total three – digit numbers = (99 – 10) + 1
                                                                          = 89 + 1 = 90
So, the total number of two – digit numbers is 90.