Irrational number approximations. Game on.

Irrational number approximations is a grade 8 math skill aligned to Common Core standard 8.NS.A.2: use rational approximations of irrational numbers to compare their size and locate them approximately on a number line diagram. Below are 8 practice questions with answers and step-by-step explanations, drawn from the 40 irrational number approximations problems our math games drill.

CCSS 8.NS.A.240 questions in the bank
Kickoff

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Warm-upeasy

Between which two consecutive integers does 40\sqrt{40} lie?

62=366^{2} = 36 and 72=49.7^{2} = 49\textsf{.} Since 36<40<49,36 < 40 < 49\textsf{,} 40\sqrt{40} is between 66 and 7.7\textsf{.}

Mid-gameeasy

27\sqrt{27} lies between two consecutive integers. Enter the larger one.

52=25<27<36=625^2 = 25 < 27 < 36 = 6^2, so 27\sqrt{27} is between 55 and 66; the larger is 66.

Mid-gameeasy

What integer is closest to 83\sqrt{83}?

92=819^2 = 81 is very close to 8383 and 83≈9.1\sqrt{83} \approx 9.1, so the closest integer is 99.

Mid-gameeasy

What is the integer part of 10+2\sqrt{10} + 2?

10≈3.16\sqrt{10} \approx 3.16, so 10+2≈5.16\sqrt{10} + 2 \approx 5.16; the integer part is 55.

Mid-gameeasy

Which is closest to π\pi?

π≈3.14159\pi \approx 3.14159.

Mid-gameeasy

Which is closest to 2\sqrt{2}?

2≈1.414\sqrt{2} \approx 1.414.

Mid-gameeasy

Which is closest to 3\sqrt{3}?

3≈1.732\sqrt{3} \approx 1.732.

Buzzer beatereasy

Which is closest to 5\sqrt{5}?

5≈2.236\sqrt{5} \approx 2.236.

Overtime

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