ADDITION AND SUBTRACTION
Properties of Addition:
- When you change the order of the addends, the sum does not change.
- The sum of any number and zero is that same number.
Adding large numbers is the same as adding smaller numbers. You start from the ones place and regroup (carry over) if necessary.
Properties of Subtraction:
- Any number subtracted from itself is zero.
- When you subtract zero from a number you get the number itself.
Subtracting large numbers is the same as subtracting smaller numbers. Write them in the correct place and start subtracting from the ones place. Regroup if necessary.