6.02 Subtract decimals
Are you ready?
Do you remember how to use a standard algorithm for subtraction? Let's try this problem to practice.
Find the value of $769-584$769−584.
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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
There are a few strategies that can be used to subtract a whole number from a number with a decimal.
This video looks at renaming numbers by filling in empty places with zeros.
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Question 1
Find $1-0.2$1−0.2 giving your answer as a decimal
Learn
Sometimes there is a need to regroup, or rename, some values before we can subtract. We use the same process as we use with whole numbers, so using place value columns can really help.
This video shows how to combine the standard algorithm for subtraction with place value columns to solve decimal subtractions that need regrouping.
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Question 2
Find $5.75-0.06$5.75−0.06, leaving your answer in decimal form.
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This video explores how to complete a pattern that involves subtracting numbers with decimals.
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Question 3
Consider the following pattern.
What is the pattern?
$0.83$0.83 $0.77$0.77 $0.71$0.71 $\editable{}$ $\editable{}$ $\editable{}$ The numbers are decreasing by $0.06$0.06.
AThe numbers are decreasing by $0.6$0.6.
BThe numbers are decreasing by $6$6.
CThe numbers are decreasing by $60$60.
D$0.83$0.83 $0.77$0.77 $0.71$0.71 $\editable{}$ $\editable{}$ $\editable{}$
When setting up the standard algorithm for numbers with decimals, we must line up the decimal points so that we are subtracting digits with the same place value.