3 Digit by 2 Digit Multiplication Math with Mr J

Welcome to Math with Mr. In this video, I'm going to cover how to multiply three-digit numbers by two-digit numbers. So, let's jump into our two examples here and find the product of each. Now, remember, product means the answer to multiplication problem. So, for number one, we have 239 * 54. And the first thing we need to do is line this problem up. So, we can write 239 * 54. Now, when writing this problem, it's important that all of our places are lined up. So, for example, our nine and four are lined up because they are both in the ones place. The three and five are lined up because they are both in the tens place. And then the two is lined up with nothing below that because 54 doesn't have digit in the hundreds place. So, now that we're lined up, we're ready to multiply. And what we're going to do, we're going to do 4 * 239 and then 50 * 239. And we're doing 50 because the five in 54 has value of 50. And then we add those two answers together to get our final product or answer. So, let's start with 4 * 9, which is 36. So, we put our six here and we carry our three that has value of 30 over to the tens place. Now, we're doing 4 * 30 because that three is in the tens place, but we can just think of it as 4 * 3 and then add that three that we carried. So, 4 * 3 is 12 + 3 is 15. Carry our one. Now, we do 4 * 200 or just think of it as 4 * 2, which is eight plus that one is nine. So, 4 * 239 is 956. But, that's not our final answer. We still need to do 50 * 239. So, we are done with this one that we carried and the three. I'm crossing those off just so we don't get confused with any other numbers we need to carry. And I'm also going to cross this four off because we are done with it. Now, we're going to do 50 * 239. So, we need zero here because we're moving over to the tens place and that five has value of 50. So, we put zero there to represent that. Now, we need to do 5 * 9, 3, and 2 just like we did with the four in our first step. So, 5 * 9 is 45. So, we put our five here, carry the four. Now, we do 5 * 3 plus that four, which is 19. Carry the one. And then 5 * 2 is 10 plus that one is 11. Now, we can add these two numbers together. These are called our partial products and it makes sense because they are part of the final product or answer. So, 6 + 0 is 6. 5 + 5 is 10. 1 + 9 is 10 + 9 is 19. 1 + 1 is 2. And we just have one there that we can drop down and we get final answer of 12,906. So, on to number two, first thing, we set the problem up, 628 * 73. So, we need to do 3 * 628 and then 70 * 628. Add those answers together to get our final answer. So, 3 * 8 is 24. Carry our two. 3 * 2 is 6 + 2 is 8. 3 * 6 is 18. We are done with this three and then also that two that we carried. So, we need zero here for our next step because that seven has value of 70. We're moving over to the tens place. So, now we do 7 * 8, which is 56. Carry our five. 7 * 2 is 14 + 5 is 19. 7 * 6 is 42 + 1 is 40 three. So, we have our partial products and we are ready to add. So, 4 + 0 is 4. 8 + 6 is 14. 1 + 8 is 9 + 9 is 18. 1 + 1 is 2 + 3 is 5. And then we have four down here. So, we get final product or answer of 45,844. So, there you have it. There's how you multiply three-digit numbers by two-digit numbers. hope that helped. Thanks so much for watching. Until next time, peace.