#### Answer

$10,648$

#### Work Step by Step

$18 + 708 + 9286 + 636$
Start at the right of each number and add the ones digits
$8 + 8 + 6 + 6 = 28$ ones
Regroup the $28$ ones as $2$ tens and $8$ ones
Write the $8$ ones in the ones column.
Write the $2$ tens in the tens column
Add the tens column next including the regrouped $2$
$2 + 1 +0 + 8 + 3 = 14$ tens
Regroup the $14$ tens as $1$ hundred and $4$ tens
Write the $4$ tens in the tens column.
Write the $1$ hundred in the hundreds column
Add the hundreds column next including the regrouped $1$
$1 + 7 + 2 + 6 = 16$ hundreds
Regroup the $16$ hundreds as $1$ thousand and $6$ hundreds
Write the $6$ hundreds in the hundreds column
Write the $1$ thousand in the thousands column
Add the thousands column next including the regrouped $1$
$1 + 9 = 10$ thousands
Regroup the $10$ thousands as $1$ ten-thousand and $0$ thousands
Write the $0$ in the thousands column and the $1$ in the ten-thousands column
Add the ten-thousands column next which is the regrouped $1$
Write the $1$ in the ten-thousands column.
$10648$
Separate each group of three digits with a comma.
The sum of the four numbers is $10,648$