Question

use simple method to compute 9+99+999+9999​

Answer 1

Answer:

You may be surprised to know there is an app or a device called calculator.

But if your question is 9+99+999 … upto n Or infinite times . Then solution is

you can write 9 as (10–1) similarly 99 as (100–1) so the solution of the 9 + 99+999…. upto n times is

(10 +100+1000+10000…. upton n times) - (1+1+1.. upto n times)

so first expression is gp with a=10 and r=10 and

Step-by-step explanation: