As President Barack Obama rightly noted in one of his first directives, his "highest priority is to keep the American people safe."[1] Addressing homeland security challenges effectively requires ...

Array formulas let you perform calculations across entire ranges of data in a single formula. Hence, you can handle lightning-fast lookups, filtering, and sorting with just one po ...

The mathematical performance of 250 U. S. sixth-grade students from both private and public schools and 425 Chinese sixth graders from both key and common schools was examined on multiple-choice tasks ...