This is a test of commonsense with single/multi-choices. Complete the next sentence:

How to buy a checkbook calculator
Measure the space in your checkbook for a calculator.
The calculator should fit inside the checkbook cover without impeding the closure of the checkbook cover. Checkbook calculators come in a variety of sizes.

Choices: *If you haven't used a checkbook all of the time, you probably don't need the calculator. If the size is larger than the width of your checkbook, however, it's probably not a good idea to purchase it. *If you use a larger calculator you may find you need 3 to 4 different sizes of calculator. Make sure the calculator you buy is compatible with your checkbook. *Generally, the most common size is 214 and the smaller an equation, the larger the calculator will be. Before making your final calculation, list the amount of money you will need. *If possible, choose a checkbook calculator with latches. The latches hook onto the checkbook cover and helps to prevent the calculator from slipping out of the checkbook.
The answer is:
If possible, choose a checkbook calculator with latches. The latches hook onto the checkbook cover and helps to prevent the calculator from slipping out of the checkbook.