The Number Sentence

Students know that there are numbers that are not rational, and approximate them by rational numbers. 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. Use rational approximations of irrational numbers to compare the size of irrational numbers, locate them approximately on a number line diagram, and estimate the value of expressions.

• 8.NS.A Know that there are numbers that are not rational, and approximate them by rational numbers.

  • 8.NS.1 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.

    • Write a repeating decimal as a fraction (8-G.4)

    • Convert between decimals and fractions or mixed numbers (8-G.5)

    • Identify rational and irrational numbers (8-I.2)

  • 8.NS.2 Use rational approximations of irrational numbers to compare the size of irrational numbers, locate them approximately on a number line diagram, and estimate the value of expressions (e.g., pi²).

    • Estimate positive square roots (8-F.2)

    • Estimate positive and negative square roots (8-F.4)

    • Estimate cube roots (8-F.10)

  • Checkpoint opportunity

    • Checkpoint: Rational and irrational numbers (8-I.4)

    • Checkpoint: Approximate irrational numbers (8-I.5)