how do you add and subtract + and - numbers? Is there a rule?

Yes. The adding rule is this: If the signs are the same, add the numbers directly, then use the sign of the numbers. If the signs are different, Subtract the smaller from the larger, and use the sign of the larger.

Example
add -4 + 2
subtract 2 from four, and used the negative sign.

example:
add -3 + -3
answer -6

The subtracting rule: Change the sign of the number being subtracted, then use the adding rule to add.

Example: Subtract -3 from 6

Change the sign of the -3 to +3, then add + 3 to 6

Example Subtract 6 from -9
change the sign of +6 to -6, then use the adding rule to add -6 to -9 to get -15

thanks!!!

Yes. The adding rule is this: If the signs are the same, add the numbers directly, then use the sign of the numbers. If the signs are different, Subtract the smaller from the larger, and use the sign of the larger.

Example
add -4 + 2
subtract 2 from four, and used the negative sign.

example:
add -3 + -3
answer -6

The subtracting rule: Change the sign of the number being subtracted, then use the adding rule to add.

Example: Subtract -3 from 6

Change the sign of the -3 to +3, then add + 3 to 6

Example Subtract 6 from -9
change the sign of +6 to -6, then use the adding rule to add -6 to -9 to get -15