JavaScript Interactive — a console crash course

1.7 Mathematical Calculations

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The JavaScript console is known to display some of the examples incorrectly in Internet Explorer 8 or older.

>>>

1 + 2 * 3

Arithmetic operators +, -, * and / all work as expected. Normal mathematical order of operations is used.

>>>

1.0E308 * 10

Infinity

Sometimes the numerical representation is just not enough.

>>>

1E309 * 1E-308 * -1

-Infinity

>>>

Number.MAX_VALUE

1.7976931348623157e+308

The Number.MAX_VALUE & Number.MIN_VALUE constants provide access to the floating-point extremes.

>>>

5 / 3

1.6666666666666667

>>>

5 % 3

Integer math is possible by using the % (modulo) operator.

>>>

- (1 + 1)

-2

The + and - operators are also unary, meaning that they can be applied to a single value.

>>>

Math.round(1.5)

A bunch of common mathematical functions are available in the built-in Math object.

>>>

isFinite(NaN) || isFinite(Infinity)

false

The global isFinite, isNaN, parseInt & parseFloat built-in functions are also useful. See the Mozilla JavaScript Reference for all details.

>>>

JavaScript Interactive — a console crash course

1.7 Mathematical Calculations

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