what are the rule for adding and subtracting positive and negative numbers
http://www.mathsisfun.com/positive-negative-integers.html
When adding and subtracting positive and negative numbers, you can follow a set of rules to help you determine the sign of the result.
1. Adding two positive numbers:
To add two positive numbers, you simply add them together, and the sum will also be positive. For example: +3 + 4 = +7
2. Adding two negative numbers:
To add two negative numbers, you again add them together, and the sum will still be negative. For example: -3 + (-4) = -7
3. Adding a positive and a negative number:
To add a positive and a negative number, you subtract the smaller absolute value from the larger absolute value, and use the sign of the number with the larger absolute value. For example: +5 + (-3) = +2. Here, we subtract the smaller absolute value (3) from the larger absolute value (5) and use the sign of the number with the larger absolute value (+).
4. Subtracting a positive number from a positive number:
To subtract a positive number from a positive number, you simply subtract the smaller number from the larger number, and the result will be positive. For example: +7 - 3 = +4
5. Subtracting a negative number from a negative number:
To subtract a negative number from a negative number, you subtract the negative number from the other negative number, which is the same as adding the absolute values together, and the result will be negative. For example: -7 - (-3) = -4. Here, we subtract the negative number (-3) from the other negative number (-7), which is equivalent to adding the absolute values together (7 + 3 = 10) and using the negative sign.
6. Subtracting a positive number from a negative number:
To subtract a positive number from a negative number, it's similar to adding a negative number to another negative number. You subtract the positive number from the negative number, and the result will be negative. For example: -5 - 3 = -8
It is helpful to remember these rules so you can quickly determine the sign of the result when adding or subtracting positive and negative numbers.