Browse · MATH Print → jmc number theory intermediate Problem Compute 997−1 modulo 1000. Express your answer as an integer from 0 to 999. Solution — click to reveal We note that 997≡−3(mod1000),and (−3)⋅333=−999=−1000+1≡1(mod1000).Therefore, 997⋅333≡1(mod1000),and the inverse of 997 modulo 1000 is 333. Final answer 333 ← Previous problem Next problem →