Teach Column Addition Of Two Digit Numbers With Regrouping

Hi, I'm Rebecca. And in this film we're going to look at formal written methods for addition using regrouping. Now, with something like this, it's really important that you give your pupils opportunity to explore it using concrete apparatus like these base 10 materials. Here, we're going to move on to the formal written method alongside the base 10. So let's look at a simple problem. Robin has 27 blocks and needs another 15 blocks to make a model. How many blocks does he need altogether? So I've already started with my numbers put into my place value chart. I've got my 27 in tens and ones and my 15 underneath. And I'm going to show how to do that as a written method. Put your tens and ones onto the page. Now I'm going to transfer. I've got 20 and 7 adding on a 10 and a 5, which makes 15. Now I'm going to come over to the place value chart and I'm going to begin by adding the ones. I've got seven, add five, Which gives me 12, but that's more than 10 ones. So at this point is where you teach the pupils how to regroup. So I'm going to regroup my 10 and I'm going to add a 10 into the tens column over here. That leaves me with two ones which I can add here. And I need to put my 10 in the tens column. Now I'm ready to come over and add up my tens. I've got 10, 20, 30, plus my other 10 from regrouping, which gives me 40. That gives me an answer of 42. So I need to return to the question, how many blocks does Robin need altogether? He needs 42. So that's formal written methods for addition with regrouping.