Video instructions and help with filling out and completing How Form 2220 Multiply

Instructions and Help about How Form 2220 Multiply

Hi and welcome to math antics in this video lesson we're gonna learn how to do basic multi digit multiplication now this can be tricky at first but don't get discouraged it just might take some extra time and practice but you'll get the hang of it one thing I want to mention before we start is that multi digit multiplication will be much easier for you if you memorize your basic multiplication facts but if you don't have them memorized then be sure to have a multiplication table handy when you're doing your practice problems okay the best way to learn this is to jump right in let's try 137 times five now as you can see this is a three digit number times a one digit number when you're given a problem like this where the numbers are written side-by-side you need to rewrite it in snacked form with the ones places lined up the way we did with addition and subtraction now you might remember with multiplication that the order of the problem doesn't matter so we could put whichever number we want on the top or the bottom but it's always best to put the number with the most digits on the top and the one with the fewest digits on the bottom there now we draw our answer line below and we put our time symbol to the left so we don't forget that we're multiplying okay now we're ready to learn the procedure for multiplying basically what we're going to do is break up this big multiplication problem and do a series of small multiplication problems or steps those small steps involve multiplying a digit and the bottom number by a digit in the top number now in our problem we only have one digit on the bottom and we're going to multiply it by each of the digits in the top number and since the top number has three digits that means that our problem will have three small multiplication steps for the first step we multiply the bottom digit 5 by the digit in the ones place of the top number which is 7 we always start with the ones place and work our way from right to left so five times seven gives us 35 now just like with addition when we get a two-digit answer we have to carry the first digit to the top of the next column because it'll be in the way of the next answer digit if we don't so the five stays down here in the ones place of the answer but the three gets carried up to the top of the tens place column now it's time for the second step we multiply the bottom digit five by the next digit to the left and our top number three so five times three equals fifteen but wait a second there's that three we carried up to the top from the last answer what do we do with that well we need to add it to the answer that we just got that's because that three was supposed to go in the tens place of the answer but just not all by itself we had to do the second multiplication step first and see what else needed to go in that answer spot with it and it turned out to be a five the second digit of the answer 15 so we have to combine the two digits that both go in that answer place that's why we add the digit we carried and we end up with 18 but once again our answer is a two digit number so we leave the eight in our answer line and we carry the one up to the top of the hundreds place column now for our third and last multiplication step we have five times one which is just 5 but again there's that digit we carried up above so it wouldn't be in the way what do you think we do with that digit yep we add it to the answer we got from the multiplication step so five plus one gives us six and that's what goes in our answer line okay then we've done all three of our multiplication steps and the answer to our problem five times 137 is 685 now that wasn't so bad was it let's try one more example before you practice some on your own let's multiply 2617 five four again we stack our problem with the ones places lined up and we make sure that the number with the most digits is on top because our top number has four digits this time it means we'll break this problem up into four smart multiplication steps we'll multiply the bottom digit by each digit in the top number starting with the ones place on the right and working our way left okay here we go with the first step we multiply the bottom digit by the top digit in the ones place four times seven equals 28 because we have a two-digit answer we need to carry the digit that'll be in the way we're gonna add it back in after complete the next multiplication step so we carry the tube to the top of the tens column and we leave the eight where it is now we can do the second step we multiply the bottom digit by the next digit in the top number four times one equals four that was easy but don't forget about that digit we carried we need to add that to our answer from the second step so four plus two gives us six and that's what we put in our answer place and this time we have a one digit answer so we don't need to carry we can just move on to the next step for our third multiplication step we'll multiply 4 times 6 that gives us