1. The problem is to round the number 3131 to the nearest ten. 2. The rule for rounding to the nearest ten is to look at the digit in the ones place (the rightmost digit). 3. If the ones digit is 5 or greater, round the tens digit up by 1. 4. If the ones digit is less than 5, keep the tens digit the same and change the ones digit to 0. 5. For 3131, the ones digit is 1, which is less than 5. 6. Therefore, we keep the tens digit (3) the same and change the ones digit to 0. 7. The rounded number is 3130.