When adding $53 + 24$ with paper and pencil, what is the most important first step to get the correct answer?

Align the numbers so the ones digits, $3$ and $4$, are in the same column.

Add the tens digits, $5$ and $2$, first.

Write the smaller number on top of the larger number.

Start by adding the first digit of each number.

A book costs 21 dollars and a video game costs 145 dollars. What combination of bills represents the total cost?

One 100-dollar bill, six 10-dollar bills, and six 1-dollar bills.

One 100-dollar bill, five 10-dollar bills, and six 1-dollar bills.

Two 100-dollar bills, six 10-dollar bills, and six 1-dollar bills.

One 100-dollar bill, four 10-dollar bills, and five 1-dollar bills.