Class 2 math (India)
Sal adds 71 + 24.
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- What does it mean by "regrouping" and "without regrouping"?(3 votes)
- Regrouping means to make ones into tens to make addition easier. For example, add 36
In order to do this, you will have to start adding on the right side. If you add 6 and 7, you will get 13. But, you can't put 13 down below the 7. So, you will have to put a 3 below the 7, and "carry" the 1 to the right side. When you add the right side, you will do 3+2+1. This is regrouping. When you do addition without using this method of "carrying the number", it is "without regrouping".(9 votes)
- can someone tell me when we will use this in real life?(8 votes)
- shouldn't the problem be 75 ?(0 votes)
- Try to pause the video and figure out what 71 plus 24 is. All right, now let's do this together. So let's think about what 71 actually means. Well we have a one in the ones place. Let me make this clear. So this is the ones place and we have one one. So that's that one one right over there. And then the tens place - in the tens place we have seven so we have seven groups of ten. One, two, three, four, five, six, seven groups of ten. So this really means seven tens and one one. This right over here, 71 boxes. Now we're going to add to that two tens. We're gonna add to that two tens; you see them here. One ten, two tens and four ones. And four ones. So what is that going to be? Well lets first thing about the ones. We have one one and four more ones. Well that's going to be five ones. That's going to be five ones, so we can count them right over there. This is five ones right over there. One one plus four ones is five ones. And then when you look at the tens; seven tens plus two tens. Well if you combine all of these together - if you combine all of these together you are going to have nine of these groups of ten. We're gonna have nine tens. Seven tens plus two tens is nine tens. So we're left with nine tens which we see right over here and five ones. And five ones. Well what's another way of saying nine tens and five ones? Well that's 95, and we're done.