MathCastle
Number TheorySuperchallengeThe Chinese Remainder Theorem

The Chinese Remainder Theorem · Superchallenge problem

How many ordered pairs (x,y)(x, y) of integers with 0≤x<10010 \le x < 1001 and 0≤y<10010 \le y < 1001 satisfy y2≡x3+x2(mod1001)y^2 \equiv x^3 + x^2 \pmod{1001}? (Here 1001=7⋅11⋅131001 = 7 \cdot 11 \cdot 13.)