Rounding Off Numbers

Find a 9-digit number, which you will gradually round off starting with units, then tenth, hundred etc., until you get to the last numeral, which you do not round off. The rounding alternates (up, down, up ...). After rounding off 8 times, the final number is 500000000. The original number is commensurable by 6 and 7, all the numbers from 1 to 9 are used, and after rounding four times the sum of the not rounded numerals equals 24.




Similar Math Riddles

A number can be multiplied by multiple of nine
i.e 9 18 27 36 45 ...

and the resulting number consist of only one digit.

Can you identify the number ?

Asked by Neha on 07 May 2023


Two friends decide to get together; so they start riding bikes towards each other. They plan to meet halfway. Each is riding at 6 MPH. They live 36 miles apart. One of them has a pet carrier pigeon and it starts flying the instant the friends start traveling. The pigeon flies back and forth at 18 MPH between the 2 friends until the friends meet.

How many miles does the pigeon travel?

Asked by Neha on 02 Aug 2021

Replace each alphabet with the number (1-9) to make the below equation correct.

AB * C = DE - F = GH / I

Asked by Neha on 29 Aug 2024


We know that the number 7 is the prime followed by a cube. Which next number is also a prime followed by a cube?

Asked by Neha on 05 Apr 2026

A Shopkeeper collects 71 rupees in the form of 20 paisa and 25 paisa.
He collects a total of 324 coins.

Can you tell me how many number of 20-paisa and 25-paisa he got?

Asked by Neha on 31 Jan 2026

Cristina learnt how to ride a horse recently. Just to test her skills, she rode the horse from her home to a mine which she covered in three minutes and returned home from the same path only this time she took four minutes. The reason was that while riding away from home, she was supported by the wind however while riding back, she was riding against the wind.

How fast do you think she could have ridden a mile if there was no wind?

Asked by Neha on 24 Oct 2026


Can you make numbers like 24, using numbers 3,3,7 & 7 with any arithmetic operator?

Asked by Neha on 25 Feb 2023

Rectify the following equality 101 - 102 = 1 by moving just one digit.

Mathematical Signs Magic

Asked by Neha on 08 Mar 2021

A large water tank has two inlet pipes (a large one and a small one) and one outlet pipe. It takes 3 hours to fill the tank with the large inlet pipe. On the other hand, it takes 6 hours to fill the tank with the small inlet pipe. The outlet pipe allows the full tank to be emptied in 9 hours.

What fraction of the tank (initially empty) will be filled in 0.64 hours if all three pipes are in operation? Give your answer to two decimal places (e.g., 0.25, 0.5, or 0.75).

Asked by Neha on 08 Jan 2026


If in a car race, the man who came two places in front of the last man finished one ahead of the man who came fifth, how many contestants were there?

Asked by Neha on 03 Feb 2023

Hot Articles

Amazing Facts

Challenging

There is a cryptic organization called Cicada 3301 that posts challenging puzzles online, possibly to recruit codebreakers and linguists.