Question 1 of 8
What is the type reported by typeof 12.5?
Think about the everyday numeric type.
A numeric literal such as 12.5 is a Number, so typeof returns "number".
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Quiz
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Test your knowledge: JavaScript Numbers
Check your understanding of Number, arithmetic, floating-point values, special values, and BigInt.
8 questions
~4 min
Beginner
Knowledge check
Test your knowledge: JavaScript Numbers
Check your understanding of Number, arithmetic, floating-point values, special values, and BigInt.
- Stuck? Each question has an optional hint.
- Skip a hard question and review it before your results.
- Questions and answer options can shuffle between attempts.
You can retake this quiz whenever you like.
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Question 2 of 8
What is 7 / 2?
Number division is not integer division.
7 / 2 evaluates to 3.5.
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Question 3 of 8
What is 17 % 5?
% gives the remainder after division.
17 divided by 5 leaves a remainder of 2.
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Question 4 of 8
Why can 0.1 + 0.2 display as 0.30000000000000004?
Think about how Number values are represented.
Number uses IEEE 754 binary64 floating-point values, so many decimal fractions are not represented exactly.
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Question 5 of 8
What does typeof NaN return?
NaN is a special value of a familiar type.
NaN is a special Number value, so typeof NaN returns "number".
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Question 6 of 8
Which is a BigInt literal?
Look for the BigInt literal suffix.
A BigInt literal uses the n suffix, such as 123n.
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Question 7 of 8
Which expression should you avoid because it mixes numeric types?
Number and BigInt are different numeric types.
Ordinary arithmetic does not permit mixing Number and BigInt operands; convert deliberately instead.
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Question 8 of 8
Which rule best describes choosing Number versus BigInt?
Choose the type from what the value means.
Number and BigInt have different semantics. The data model and precision requirements should determine the choice.
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Quiz results
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Review
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What is the type reported by typeof 12.5?Hint used
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What is 7 / 2?Hint used
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What is 17 % 5?Hint used
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Why can 0.1 + 0.2 display as 0.30000000000000004?Hint used
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What does typeof NaN return?Hint used
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Which is a BigInt literal?Hint used
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Which expression should you avoid because it mixes numeric types?Hint used
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Which rule best describes choosing Number versus BigInt?Hint used