Answer
$328$
Work Step by Step
$172 + 156$
Start at the right of each number and add the ones digits
$2 + 6 = 8$ ones
Write the $8$ ones in the ones column.
Add the tens column next
$7 + 5 = 12$ tens
Regroup the $12$ tens as $1$ hundred and $2$ tens
Write the $2$ tens in the tens column.
Write the $1$ hundred in the hundreds column
Add the hundreds column next including the regrouped 1
$1 + 1 + 1 = 3$ hundreds
Write the $3$ hundreds in the hundreds column
The sum of the two numbers is $328$