Grade 3 Valentine's Day Adding Three-Digit Numbers Math Riddle Worksheet! This fun and festive worksheet is perfect for second and third-grade students looking for a little holiday math fun. This worksheet features Valentine's Day-themed math riddle and instructions on how to solve it. Students will need to add three-digit numbers to solve the riddle, and they'll love the challenge of cracking the code. This is a great way to review addition skills and get into the Valentine's Day spirit!