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.

All of Jacob's shoes are red except two.
All of Jacob's shoes are green except two.
All of Jacob's shoes are yellow except two.

How many shoes does Jacob have?

How do you go from 98 to 720 using just one letter?

Can you find out which number multiplied by itself will give the output as 12345678987654321?

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

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

which number am I?

Replace the question mark with the correct number, given the pair of numbers exhibits a similar relationship?

? : 3839 :: 11 : 1209

I am an odd number. Take away a letter and I become even. What number am I?

In the image below, can you find the value of an angle(y)

Can you find out the remainder when 3^300 is divided by 5?