How to set a quantity by entering an exact number, or a difference (add/substract amount)?

1. What is the rule for adding and subtracting measured numbers?
2. How do you do addition and subtraction in the same problem?
3. When adding or subtracting measured values the result should?

What is the rule for adding and subtracting measured numbers?

Count the number of significant figures in the decimal portion ONLY of each number in the problem. Add or subtract in the normal fashion. Your final answer may have no more significant figures to the right of the decimal than the LEAST number of significant figures in any number in the problem.

How do you do addition and subtraction in the same problem?

To show the problems involving both addition and subtraction, we first group all the numbers with '+' and '-' signs. We find the sum of the numbers with '+' sign and similarly the sum of all the numbers with '-' sign and then find the difference. If there is no sign before a number it means '+' sign.

When adding or subtracting measured values the result should?

When adding or subtracting measured quantities, the result will be determined by the quantity with the least number of decimals places.