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2.03 Addition with regrouping


Are you ready?

Did you get the hang of adding 3 or 4 digit numbers together?

Find the value of $270+520$270+520.


When we add numbers, we can break our numbers up (partition) and add the parts in a different order. Let's see how doing this helps us, in this video.


Question 1

Let's find the value of $705+205$705+205, by partitioning the numbers.

  1. Fill in the box with the missing number.


  2. Fill in the box with the missing number.


  3. Find the value of $705+205$705+205.


What happens with larger numbers? We can see in this video that writing our numbers down the page helps us with trading, or regrouping. Let's use a vertical algorithm to solve one.


Question 2

Find the value of $6118+8628$6118+8628.


Whenever we get more than $9$9 for one of the digits in our number, we have to regroup, or trade, to the next place value. All we need to remember is that we can trade $10$10 of any place for $1$1 of the places to the left.



Apply place value to partition, rearrange and regroup numbers to at least tens of thousands to assist calculations and solve problems

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