# Numbers

Arbitrary-precision fixed-point decimal numbers.

Ghost has a single numberic type; arbitrary-precision fixed-point decimals. While most other languages contain representations for integers, floats, doubles, etc., we found that having just a single number type was easier to use even at the slight cost of performance.

Because Ghost uses an arbitrary-precision fixed-point decimal system, it is extremely accurate. Number values look like you expect from other languages:

```
0
1234
-5678
0.001
3.14159
12.34
-1.76
```

## Precision

Float point numbers (or any binary floating point type) can't represent fractional decimals (`0.1`

) precisely. When adding and subtracting them repeatedly will cause rounding errors.

For example, let's consider this code in Go:

```
package main
import "fmt"
func main() {
var n float64 = 0
for i := 0; i < 1000; i++ {
n += .01
}
fmt.Println(n)
}
```

You might expect it to print `10`

, but it in fact prints `9.999999999999831`

. This may not be so much of an issue, but if you were having to calculate with extreme precision (such as money), you could find yourself short a few dollars in some extreme cases.

If you were to run the same program above in Ghost, you'd find that the result does come out to exactly `10`

:

```
value = 0
for (i = 0; i < 1000; i = i + 1) {
value = value + 0.01
}
print(value)
// expected value: 10
```

## Scientific Notation

Numeric values can be represented in scientific notation by using `e`

. This returns a value multiplied by the specified power of `10`

.

```
1.1 // expected value: 1.1
1.1e0 // expected value: 1.1
1.1e1 // expected value: 11.0
1.1e2 // expected value: 110.0
1.1e3 // expected value: 1100.0
8e-2 // expected value: 0.08
```

## Methods

`round()`

The `round()`

method rounds the given number to the nearest integer to the specified precision.

```
value = 123.4.round()
// expected value: 123
```

```
value = 123.456.round(1)
// expected value: 123.5
```

`toString()`

The `toString()`

method returns the given number as a string.

```
value = 3.141592.toString()
// expected value: "3.141592"
```