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8th grade Kinds of real numbers: rational and irrational worksheet

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Kinds of real numbers: rational and irrational

Grade 8 Math Worksheet - Challenge Me

NameDate

Circle the best answer, or write your answer on the line.

  1. Kira deals six cards from a number deck: √196, √77, π, 0.8, 0.3636…, √88. How many of the cards show an irrational number?

  2. Luz deals seven cards from a number deck: √225, √56, √91, √95, √78, 0.9, 0.7272…. How many of the cards show an irrational number?

  3. Pia picks cards −18, √41 and 0. What is the smallest group that holds all of these numbers?

    • integers
    • real numbers
    • irrational numbers
    • rational numbers
  4. Ren picks cards √17, 9, π and 0.5. What is the smallest group that holds all of these numbers?

    • rational numbers
    • irrational numbers
    • real numbers
    • integers
  5. Ari gets two clues about a mystery number: it is a real number, and it is not rational. Which number fits both clues?

    • 6.4
    • 0.1818…
    • √64
    • √48
  6. Read this first

    Use this

    Number line from -4 to 4, ticks every 1. Green marks are whole numbers, blue marks the other integers, orange marks the other rational numbers, and purple marks irrational numbers. The real numbers are every mark on the line.

  7. Bo reads four claims about number groups on a sticky note. Which claim is true?

    • Every real number is an integer.
    • Every integer is a real number.
    • Irrational numbers have no place on the number line.
    • Every square root is an irrational number.
  8. Jun reads four claims about number groups on a sticky note. Which claim is true?

    • Rational and irrational numbers together make up all the real numbers.
    • Rational numbers make up all the real numbers.
    • Whole numbers, integers and rational numbers make up the irrational numbers.
    • Irrational numbers make up all the real numbers.
  9. Kira says √26 is irrational. Which reason is best?

    • 26 is not a perfect square, so the decimal never ends or repeats.
    • 26 is a big number, so √26 must be irrational.
    • 26 is not a perfect square, so the decimal stops after a few digits.
    • √26 has a root sign, and every square root is irrational.
  10. Use this

    Number line from 0 to 2, ticks every 1. Green marks are whole numbers, blue marks the other integers, orange marks the other rational numbers, and purple marks irrational numbers.

  11. Luz says 0.2727… is rational. Which reason is best?

    • Its digits go on forever, so it cannot be a fraction.
    • All decimals are rational.
    • It is less than 1, so it is rational.
    • The block 27 repeats, so it can be written as a fraction.
  12. Use this

    Number line from 0 to 5, ticks every 1. Green marks are whole numbers, blue marks the other integers, orange marks the other rational numbers, and purple marks irrational numbers.

  13. Milo says π is irrational. Which reason is best?

    • π is a circle number, so it cannot be real.
    • π equals 3.14, which stops, so it is a fraction.
    • π = 3.1415926… and its digits never end or repeat.
    • π equals 22/7, so it is a fraction.
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8th grade Kinds of real numbers: rational and irrational worksheet – printable
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About this worksheet

Kinds of real numbers: rational and irrational. Every version has 10 questions, and the answer key prints on the second page.

What your child will learn

  • I can tell whether a number is rational or irrational and say why: its decimal stops or repeats, or it never ends and never repeats.
  • I can name the smallest group that holds a number, or a whole list of numbers, and I know the rational and irrational numbers together make up the real numbers.

Standard: 8.NS.A.1 (irrational numbers)

Words to know

rational number: A number you can write as a fraction. Its decimal stops or repeats.

irrational number: A number with a decimal that never ends and never repeats, like π.

real number: Any number that has a mark on the number line.

perfect square: A number you get by multiplying a whole number by itself: 49 = 7 × 7.

square root (√): The number that, multiplied by itself, gives the number under the sign.

repeating decimal: A decimal with a block of digits that repeats forever, like 0.4545….

Common mistakes

Your child treated every square root as irrational.

Your child read a calculator's short decimal for a square root as if it ended.

Your child rounded a square root to a whole number and called it whole.

What to say

Ask: what is the square root of 49? Does it come out exactly?

Ask: do the digits of the square root of 2 stop, or do they keep going with no pattern?

Ask: is the square root of 20 exactly 4 or exactly 5?

Questions parents ask

What is the most common mistake with kinds of real numbers: rational and irrational?

Your child treated every square root as irrational.

How can I help my child with kinds of real numbers: rational and irrational?

Ask: what is the square root of 49? Does it come out exactly?

Are these 8th grade math worksheets free to print?

Yes. All 6 printable versions at each level are free to print, with the answer key, and no account is needed.

More grade 8 math

See all grade 8 math

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