Chapter 1 - Whole Numbers - 1.7 Rounding Whole Numbers - 1.7 Exercises - Page 74: 61

76 million rounds to 80 million; 311 million rounds to 310 million.

In 76 million, the digit right of the ten-millions place is 6, so we round up to the next biggest ten-million and change 7 to 8 to get 80 million. In 311 million, the digit right of the ten-millions place is 1, so we round down and keep the 1 the same to get 310 million.