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

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


By using all numbers, i.e. 123456789 and subtraction/addition, operators number 100 can be formed in many ways.
Example: 98 + 7 + 6 - 5 - 4 - 3 + 2 - 1 = 100

But if we add a condition use of the number 32 is a must. Then there are limited solutions.
One of such solution is: 9 - 8 + 76 + 54 - 32 + 1 = 100

Can you tell me any other solution?

Asked by Neha on 10 Aug 2024

Can you think of a smallest +ve number such that if we shuffle the digits of the number, the new number becomes double the original number?

Asked by Neha on 25 Feb 2024


Check out the number list below and find what number comes next in the sequence.

111 , 113 , 117 , 119 , 123 , 137 , ?

Asked by Neha on 30 Mar 2026

An express train takes 3 seconds to enter the tunnel which is 1 km long.
If it is travelling at 120 km an hour, how long will it take to pass completely through the tunnel?

Asked by Neha on 26 Nov 2023

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


If "P" means "-", "Q" means "/", "R" means "+", and "S" means "*" then find the value of the following:

21 Q 7 R 9 S 10 P 13

Asked by Neha on 16 Oct 2025

In a town, there are four houses located at different distances from each other. Following are the distances:

The third house is 60 meters apart from the first house.
The fourth house is 40 meters apart from the second house.
The third house is 10 meters nearer to the fourth house than it is to the second house.

Can you find out the distance between the fourth and the first house?

Asked by Neha on 14 Sep 2024

Using four sevens (7) and a one (1) create the number 100. Except for the five numerals, you can use the usual mathematical operations (+, -, x, :), root and brackets ()

Asked by Neha on 26 May 2023


John replied, when asked how old he was. In 2 years he will be twice as old as he was five years ago.' How old is he ?

Find the age

Asked by Neha on 10 Apr 2021

Hot Articles

Amazing Facts

Rubik’s Cube

The inventor of the Rubik’s Cube didn’t realize he’d built a puzzle until he scrambled it the first time and tried to restore it.