№2. Округлите: a) до тысяч: 31902873 ; б) до сотен тысяч: 186276501 ; в) до миллионов: 99857318.

To round the numbers as specified, follow these steps: a) Round 31,902,873 to the nearest thousand: - Look at the hundreds digit, which is 8. - Since 8 is greater than or equal to 5, round up the thousands digit. - The thousands digit is 2, so it becomes 3. - All digits to the right of the thousands place become 0. - The rounded number is 31,903,000. b) Round 186,276,501 to the nearest hundred thousand: - Look at the ten-thousands digit, which is 7. - Since 7 is greater than or equal to 5, round up the hundred-thousands digit. - The hundred-thousands digit is 6, so it becomes 7. - All digits to the right of the hundred-thousands place become 0. - The rounded number is 186,280,000. c) Round 99,857,318 to the nearest million: - Look at the ten-thousands digit, which is 7. - Since 7 is greater than or equal to 5, round up the millions digit. - The millions digit is 9, so it becomes 10, which means we add 1 to the next higher place value (hundreds of millions). - The hundreds of millions digit is 0, so it becomes 1. - All digits to the right of the millions place become 0. - The rounded number is 100,000,000. So, the rounded numbers are: a) 31,903,000 b) 186,280,000 c) 100,000,000