4.01 Relate addition and subtraction
Are you ready?
We're going to look at how addition and subtraction are related, and number lines can help us with that. Do you recall how to use a number line to work out subtraction problems?
Use the number line to help you find the value of $35-24$35−24.
$35-24$35−24$=$=$\editable{}$
Learn
We can see how addition and subtraction are related by looking at their fact families, just like in this video.
Apply
Using the fact family of $5$5, $7$7, and $12$12.
 |
$+$+ |  |
$=$= |  |
| $7$7 | $+$+ | $5$5 | $=$= | $12$12 |
What is $5+7$5+7?
What is $12-7$12−7?
What is $12-5$12−5?
There are four different number sentences we can make for each fact family, two addition and two subtraction. If we start with the numbers, $12$12, $13$13 and $25$25, we can make the following fact family:
$12$12 + $13$13 = $25$25
$13$13 + $12$12 = $25$25
$25$25 - $13$13 = $12$12
$25$25 - $12$12 = $13$13