Remember the goal of rounding is to be able to calculate the problem easily and quickly. It is different from truncating because with rounding you have a choice to make. Imagine the number 6,834 being on a rope and standing between the number 6,000 and 7,000. Both round numbers are engaged in a number tug of war trying to pull the 6,834 to their side. So how do you know who wins?
Follow these steps.
1. Dizzy Digits. First decide what place you want to round to. How many digits can dance in your head before you get dizzy? 6,834 + 2,378 = is too complicated.
2. Underline what you are going to keep. 6,834 + 2,378
3. Tug of War. Look closely at the digit to the right of the underlined digit 6. How strong is that digit? Remember the tug of war? If both sides pulled the underlined digit which one would win? Will the digit get pulled up or stay the same? The secret is to remember that a number must be 5 or greater to pull the underlined number up, and it must be 4 or less to keep the unlined number the same. The 8 is strong, so the digit increases by one. You add one, and the 6 becomes a 7.
4. Bring on the Donuts. Use your donut machine to make the digits you’ve taken out zeroes. You removed the 834, so 6,834 becomes 7,000. You call it rounding up because the number got bigger. If the number got smaller you would call that rounding down.
After you round the second number follow the next step.
5. Calculate. 7,000 + 2,000 = 9,000.