Answer
$72$ feet (ft.) of lumber
Work Step by Step
To find the amount of lumber we will find the distance around the entire patio, we will add the three sides (18, 30, 24)
$18 + 30 + 24$
Start at the right of each number and add the ones digits
$8 + 0 + 4 = 12$ ones
Regroup the $12$ ones as $1$ ten and $2$ ones
Write the $2$ ones in the ones column.
Write the $1$ ten in the tens column
Add the tens column next including the regrouped $1$
$1 + 1 + 3 + 2 = 7$ tens
Write the $7$ tens in the tens column.
The sum of the three numbers is $72$
The distance is $72$ feet (ft).
