how do you get the answer 2 for the following question 999888777666555444352 when mod 25

Note the following points. (i) x\mod 25 means the remainder when x is divided by 25. (ii) Any multiple of 25 will end with either 00 or 25 or 50 or 75 So it doesn't matter how big the given number x is, just by observing the last two digits we can find the remainder when it is divided by 25. Here, in the given number 52 is the last two digits. And 52= 50+2, that is, 2 greater than a multiple of 25. So when we divide the number x by 25, the remainder will be 2. That is x \mod 25 = 2