Hey there! Hello!
There are a few different ways you could represent subtraction. One of which is by using a circle or other shape to represent each number in your problem, which is 12, then cross out the number you want to take away. You can see this in the higher portion of my attachment.
Another method you could use is a number line. In the lower portion of the attachment, you can see how I start at 12 then move towards zero three times.
In both instances, you can see that 12 – 3 is equal to nine.
Hope this helped you out! Feel free to ask any additional questions if you have any. :-)
