PRACTICE: Addition and subtraction using an algorithm
Practice
Before you practice the work from this chapter, take some time to go over how we were able to use place value columns to set up a standard algorithm. This is useful to solve addition and subtraction problems, instead of using:
- place value models
- number lines
- partitioning to break our numbers up
We also looked at how to use a standard algorithm to solve addition or subtraction where we needed to regroup our numbers.
We also saw a mix of addition and subtraction problems of different lengths, where we may, or may not, need to do some regrouping.
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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.
Apply
Question 1
Find the value of $333+451$333+451.
Question 2
Find the value of $9334+284$9334+284.
Question 3
Find the value of $9743+9172$9743+9172.
When we use a standard algorithm, we need to make sure our digits are lined up so they are in the correct place. If we need to regroup, we regroup to the left for addition, and to the right for subtraction.