MathCastle
Grade 4SuperchallengeMulti-Digit Multiplication

Multi-Digit Multiplication · Superchallenge problem

When you multiply 213×3213 \times 3 with the standard algorithm, you never have to carry: 3×3=93 \times 3 = 9, 1×3=31 \times 3 = 3, 2×3=62 \times 3 = 6, so the answer is 639639. How many three-digit numbers can be multiplied by 33 with no carrying at all (and give a three-digit answer)?