WEBVTT
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Complete the pattern: 2.7, 1.9, 1.1, what.
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The pattern that we’ve been given here involves decimal numbers.
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We have three decimal numbers and then a missing number, which is the number we need to find to complete the pattern.
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Looking for patterns in decimal numbers is not always very easy to do.
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We’re not always used to thinking in terms of tenths and hundredths and so on.
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One method that we could use to help us is to write each number without the decimal point.
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Really, this is the same as multiplying each decimal by 10, shifting the digits one place to the left.
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So 2.7 would become 27, 1.9 would become 19, and 1.1 would become 11.
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Our reason for doing this is that we’re now dealing with whole numbers.
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And it might be easier to spot a pattern this way.
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The pattern is certainly decreasing.
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And to get from 27 to 19, we’d need to subtract eight.
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And if we subtract eight from 19, we get 11.
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So we can see this idea of subtracting eight each time is the rule for the whole sequence.
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So the missing number in this whole number sequence will be the answer to 11 take away eight, which, of course, is three.
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Now, we can use everything that we’ve just found out and apply it to our pattern of decimals.
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Everything remains the same, except it’s worth 10 times less.
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Remember, we multiplied each decimal by 10 and made it a whole number.
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So everything became 10 times greater.
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We said the rule for our whole number pattern was to subtract eight.
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So the number we need to subtract for our decimal pattern needs to be 10 times less than eight.
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This is eight-tenths or 0.8.
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So the missing number in our problem is going to be the answer to 1.1 take away 0.8.
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Instead of three, the answer is going to be 10 times less than three.
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So the answer is going to be 0.3.
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Our completed pattern is 2.7, 1.9, 1.1, 0.3.
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The missing number that we used to complete the pattern was 0.3.