10-digit calculator features an extra-large LCD that displays crisp, clear digits to prevent reading errors. Durable keys are appropriately spaced for fast, accurate data entry. Backspace key allows you to make quick, single-digit corrections for time-saving use. Twin-power operation runs on solar energy with a battery backup to provide consistent, reliable performance in any environment. Handheld calculator also includes automatic tax keys, percent key, square root key, four-key independent memory, automatic power down and more.