Description: Learn to multiply a 3-digit number by a 1-digit number without regrouping. In this video, we will multiply 4x201. Created by Sal Khan. Let's multiply 4 times 201 just to simplify things a little bit. Now, just like we did when we were multiplying a one digit times a two digit, we do essentially the same process. So we put a 4 right over there in the ones place.*Teacher Advisor is 100% free.