You may have already looked at how to write a rule to describe number patterns. Now we are going to extend this and learn how to write general rules using pronumerals.

A pronumeral is a letter mathematicians use to represent an unknown value. Watch this value to see how we can use pronumeral to describe patterns with fractions.

Worked examples

Question 1

Complete the following pattern.

$0.01$0.01 $0.02$0.02 $0.03$0.03 $\editable{}$ $\editable{}$ $\editable{}$ $\editable{}$ $\editable{}$
If $c$c belongs to the same pattern, what is the next number?

Question 2

Complete the following pattern.

$0.15$0.15 $0.14$0.14 $0.13$0.13 $\editable{}$ $\editable{}$ $\editable{}$ $\editable{}$ $\editable{}$
If $x$x belongs to the same pattern, what is the next number?

Question 3

Consider the following pattern.

What is the pattern?

$0.03$0.03 $0.11$0.11 $0.19$0.19 $\editable{}$ $\editable{}$ $\editable{}$

The numbers are increasing by $0.08$0.08.
A
The numbers are increasing by $80$80.
B
The numbers are increasing by $8$8.
C
The numbers are increasing by $0.8$0.8.
D
Now complete the pattern.

$0.03$0.03 $0.11$0.11 $0.19$0.19 $\editable{}$ $\editable{}$ $\editable{}$
If $x$x belongs to the same pattern, what is the next number?

Outcomes

NA4-2

Understand addition and subtraction of fractions, decimals, and integers

NA4-9

Use graphs, tables, and rules to describe linear relationships found in number and spatial patterns

Generalising patterns with fractions in tenths or hundredths