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.

What's a single-digit number with no value?

In a school, there are four subjects. Seventy percent of students study English, seventy five percent of students study Science, eighty five percent of students study Mathematics and eighty percent of students study Spanish.

Can you calculate the percentage of students that study all four subjects?

Krish is 45 years old and his mother Crishtina is 73 years old.

Can you find out how many years ago, his mother was three times his age?

Using mathematical symbols like +, -, and x in order to make the equations correct. Replace # with the above-given symbols.

9 # 8 # 7 # 6 # 5 # 4 = 91

Which three-digit number, made of consecutive digits, like 567, is 2 less than a cube and 2 more than a square?

Find the combined weight of the Cat, Dog and Rabbit in the given picture.

Double it and multiply it by 4. Then divide it by 8 and you’ll have it once more. What number is it?

How many pluses should we put between the digits of 987654321 to get a total of 99, and where?

I am a prime number.
The double of myself is equal to the square of me.

which number am I?