12-digit calculator features durable, color-coded keys that stand out from each other for easier identification. Extra-large LCD clearly displays sharp, crisp digits to help prevent reading errors. Cost-sell-margin keys allow fast, simple profit margin calculations. Twin-power operation runs on solar energy with a battery backup to deliver consistent, reliable use in any environment. Backspace key allows you to make quick, single-digit corrections for timesaving use. Desktop calculator also includes four-key independent memory key, double-zero key, change sign key, percent key, grand total key, automatic power down and more.