2. Addition and subtraction

Lesson

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.

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

Fill in the box with the missing number.

$705=700+\editable{}$705=700+

Fill in the box with the missing number.

$205=\editable{}+5$205=+5

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.

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

Remember!

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