# How can I check if a number is even or odd using JavaScript?

## Using the modulo operator

The modulo operator (`%`) returns the remainder of a division operation. Given that, we can check if a number is even or odd by dividing it by `2` and checking the remainder. If the remainder is `0`, the number is even, otherwise it's odd.

```const isEven = num => num % 2 === 0;
const isOdd = num => num % 2 === 1;

isEven(3); // false
isOdd(3); // true```

## Using the bitwise AND operator

The bitwise AND operator (`&`) returns `1` if both bits are `1`, otherwise it returns `0`. The binary representation of an even number always ends with `0`, while the binary representation of an odd number always ends with `1`. As such, applying the bitwise AND operator to a number and `1` will return `0` for even numbers and `1` for odd numbers. In order to convert this result to a boolean, we can use the `Boolean()` function.

```const isEven = num => !Boolean(num & 1);
const isOdd = num => Boolean(num & 1);

isEven(3); // false
isOdd(3); // true```

### Notes

• While both approaches work, the modulo operator is more readable and should be preferred.
• Apart from these two approaches, other bitwise operators, such as the bitwise XOR operator (`^`), can also be used to check if a number is even or odd.

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