Final answer:
To round off 456,670 to the nearest ten thousand, look at the ten thousand place which is 5 and the number following it, which is 6. Since this number is 5 or greater, round up 456,670 to 460,000.
Step-by-step explanation:
To round off 456,670 to the nearest ten thousand, we must identify the digit in the ten thousand place and look to the right to decide how to round. For 456,670, the ten thousand digit is 5 and the digit to the right is 6. According to rounding rules, if the digit to the right is 5 or greater, we round up. Therefore, we round up 456,670 to 460,000.