See https://www.geeksforgeeks.org/multiplicative-inverse-under-modulo-m/ Also note that 44 * 113636380 % (10**9 + 9) = 675 Since the modulo operation is not distributive over division we can't directly calculate 675/44 (mod 10^9 + 9). Instead, we find the multiplicative inverse of 44 (ie. 1/44) and use that (as discussed in the article). For more info on why we use the modulo operation read https://www.hackerearth.com/practice/notes/abhinav92003/why-output-the-answer-modulo-109-7/