Answer:
-3.2
Explanation:
This is the longer explanation.
-12.4+9.2 let's start with the tenth values.
On a number line, when you're adding a positive number to a negative number you go up. -.4+.2 would be -.2, but if that's too difficult imagine if it was tens place meaning -4+2 which would equal 2 but the difference is you have to add the decimal in this problem. So the answer is -.2.
Now, we are adding 9 to -12. On a number line, think of it as being positioned at -12 and having to go up 9 times because remember when you're adding a positive number to a negative number you go up. When you go up the number line 9 times you stop at -3. When you go back down subtracting 9, you'll be placed at -12. So our answer is -3.
-3.0+-.2= -3.2. When you add -.2 to -3 you end up with -3.2. Line it up as a typical addition problem if you need to.