2.02 Addition with regrouping
Are you ready?
Do you remember how to add $3$3 or $4$4 digit numbers together?
Find the value of $242+357$242+357.
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Another word that we can use to describe the ones place is 'units'.
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You might notice that sometimes the standard algorithm is called the 'vertical algorithm'. Let's think about why. When we use the standard algorithm, we line our numbers up in 'vertical' place value columns.
Learn
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.
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Question 1
Let's find the value of $205+305$205+305, by partitioning the numbers.
Fill in the box with the missing number.
$205=200+\editable{}$205=200+
Fill in the box with the missing number.
$305=\editable{}+5$305=+5
Find the value of $205+305$205+305.
Learn
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 standard algorithm to solve one.
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Question 2
Find the value of $9119+6215$9119+6215.
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.