1. Make sense of problems and persevere in solving them. 2. Reason abstractly and quantitatively. 3. Attend to precision. 4. Know that there are numbers that are not rational, and approximate them by rational numbers. 5. Know that numbers that are not rational are called irrational. Understand informally that every number has a decimal expansion; for rational numbers show that the decimal expansion repeats eventually, and convert a decimal expansion which repeats eventually into a rational number.