Chapter 1 - Whole Numbers - 1.2 Adding Whole Numbers - 1.2 Exercises - Page 20: 81

$20,157$ students are enrolled

The problem asks for a total. A total is the answer to an addition problem. Therefore, we will add the three numbers (13,786 students enrolled in on-campus day classes, 3497 students enrolled in night classes, and 2874 students enrolled on on-line classes). $13,786 + 3497 + 2874$ Start at the right of each number and add the ones digits $6 + 7 + 4 = 17$ ones Regroup the $17$ ones as $1$ ten and $7$ ones Write the $7$ ones in the ones column. Write the $1$ ten in the tens column Add the tens column next including the regrouped $1$ $1 + 8 + 9 + 7 = 25$ tens Regroup the $25$ tens as $2$ hundreds and $5$ tens Write the $5$ tens in the tens column. Write the $2$ hundreds in the hundreds column Add the hundreds column next including the regrouped $2$ $2 + 7 + 4 + 8 = 21$ hundreds Regroup the $21$ hundreds as $2$ thousands and $1$ hundred Write the $1$ hundred in the hundreds column Write the $2$ thousands in the thousands column. Add the thousands column next including the regrouped $2$ $2 + 3 + 3 + 2 = 10$ thousands Regroup the $10$ thousands as $1$ ten-thousand and $0$ thousands Write the $0$ thousands in the thousands column. Write the $1$ ten-thousand in the ten-thousands column Add the ten-thousands column including the regrouped $1$ $1 + 1 = 2$ ten-thousands Write the $2$ in the ten-thousands column $20157$ Separate each group of three digits with a comma. The sum of the three numbers is $20,157$ $20,157$ students are enrolled.