Question

How many four digits numbers are there in all and how

Answer 1

Answer:

9999

Step-by-step explanation:

I think this this will help u

1000-9999

Answer 2

The smallest 4 digit number = 1000

The largest 4 digit number = 9999

1000, 1001, 1002, ........ 9999 are in A.P

(Arithmetic Progression)

Consider the formula,

aₙ = a + ( n - 1 )d

Where

aₙ = The last term

a = The first term

n = Number of terms

d = Common difference

$9999 = 1000 + (n - 1) 1 \\9999 = 1000 + n - 1 \\9999 - 1000 + 1 = n \\n = 9000$

$\boxed{\boxed{\bold{Therefore, \ there \ are \ 9000 \ numbers \ from \ 1000 \ to \ 9999}}}}$