Rounding to the Nearest 100

To round to the nearest 100, look at the tens digit. If the tens digit is 0, 1, 2, 3, or 4, round down. If it is 5, 6, 7, 8, or 9, round up. 370 has a 7 in the tens place, so round up to 400. 320 has a 2, so round down to 300.