Rational and irrational numbers
Classify, compare, and order numbers in the real number system, including rational numbers and irrational square roots. Unlimited questions, five difficulty levels, and a full worked solution every time — free.
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Is sqrt(7) a rational number or an irrational number?
Answer: irrational
See one solved, step by step
Is -sqrt(21) a rational number or an irrational number?
📘 Worked solution
121 is not a perfect square.No whole number, multiplied by itself, gives exactly 21.
2It is irrational.The negative sign doesn't change that -- the decimal still never terminates or repeats.
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