UK Primary (3-6) Represent relationships using tables and descriptions
Lesson

## Input and output tables

We've seen how we can find patterns to help us solve number problems, with addition and subtraction, but what if we wanted to use a pattern to help us fill in a table like the one below?

Input Output
3 7
4
9
6 10

Let's look at how we do this. Video 1 shows us some strategies to fill in the table.

## When the output is smaller

Sometimes we might find the data in the output is smaller than the input numbers. That's okay, it means we need to think about whether subtraction or division is needed. You may use your knowledge of turnaround facts or fact families to help. Just like we saw in Video 1, we can use our earlier solutions to help us fill in the gaps.

## Writing an equation

An equation is a number sentence. In our final video, not only do we fill in the missing information in the table, we also complete an equation that tells us the rule, or how the input and output are related to each other! See if you can write a different equation, at the end, for the same table.

#### Worked Examples

##### Question 1

Complete the table by filling in the missing values:

1. IN OUT
$14$14 $20$20
$\editable{}$ $21$21
$16$16 $22$22
$17$17 $\editable{}$
$18$18 $24$24
$19$19 $25$25

##### Question 2

Complete the table by filling in the missing values:

1. IN OUT
$9$9 $\editable{}$
$21$21 $7$7
$30$30 $10$10
$33$33 $11$11
$42$42 $14$14
$\editable{}$ $16$16

##### Question 3

Bart knows that he is older than his sister Isabelle. The following table shows his sister's age compared to his age.

1. Fill in the missing values.

Bart's age Isabelle's age
$10$10 $7$7
$11$11 $8$8
$15$15 $\editable{}$
$20$20 $17$17
$\editable{}$ $27$27
2. If we use $n$n to represent Isabelle's age, and $a$a to represent Bart's age, complete the rule:

$n=a-\editable{}$n=a