Topics
5. Decimals
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AustraliaNSW
Stage 3

5.07 Decimal patterns

Lesson
Practice
Lesson

Are you ready?

We have previously learned how to  represent numbers as words and symbols,  specifically decimals. Let's review.

Examples

Example 1

How do we write the number 0.53 in words?

A
fifty three tenths
B
five tenths
C
fifty three hundredths
Worked Solution
Create a strategy

Use a place value table.

Apply the idea

Write the number in the place value table.

Units.TenthsHundredths
0.53

We can see in the table that we have 5 tenths and 3 hundredths. This can also be written as "fifty three hundredths". So the answer is option C.

Idea summary

A place value table is useful when writing a decimal in words.

Patterns with decimals

This video looks at how to identify the rule and continue a pattern.

Loading video...

Examples

Example 2

Complete the pattern: 4.2, \, 4.0, \, 3.8, \, ⬚, \, ⬚, \, ⬚ .

Worked Solution
Create a strategy

Find how much the numbers are decreasing by each time and subtract that to the last value to complete the pattern.

Apply the idea

To work out how much the numbers are decreasing by each time, you can count up or find the difference between the numbers.

\displaystyle 4.2 - 4.0\displaystyle =\displaystyle 0.2Find the difference

Subtract this result to the last number to complete the pattern.

\displaystyle 3.8 - 0.2\displaystyle =\displaystyle 3.6Subtract 0.2 from 3.8
\displaystyle 3.6 - 0.2\displaystyle =\displaystyle 3.4Subtract 0.2 from 3.6
\displaystyle 3.4 - 0.2\displaystyle =\displaystyle 3.2Subtract 0.2 from 3.4

The complete pattern is 4.2, \, 4.0, \, 3.8, \, 3.6, \, 3.4, \, 3.2.

Idea summary

If we say the decimals out loud, we can often hear the pattern. By saying 22 hundredths, 24 hundredths, 26 hundredths, and so on, we can see that for 0.22, \, 0.24, \, 0.26, we have 2 more hundredths each time.

Outcomes

MA3-8NA

analyses and creates geometric and number patterns, constructs and completes number sentences, and locates points on the Cartesian plane

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