# Generic type variables

### `Number<`<mark style="color:green;background-color:green;">`Value`</mark>`>`

#### <mark style="color:green;">`Value`</mark>`extends`[<mark style="color:green;">`number`</mark>](https://www.typescriptlang.org/docs/handbook/basic-types.html#number)

​A generic type variable constrained by the [`number`](https://www.typescriptlang.org/docs/handbook/basic-types.html#number), by default of the value **captured** from the supplied [`value`](https://range.angular-package.dev/draft/constructor#value-value) indicates the [primitive value](https://range.angular-package.dev/draft/methods/valueof#number.prototype.valueof) type of a new [`Number`](https://range.angular-package.dev/draft/number) instance.

{% code title="number.class.ts" %}

```typescript
class Number<
  Value extends number // <--- Declare generic type variable Value.
> extends Inequality<Value> {
  constructor(
    value: Value // <--- Capture generic type variable Value.
  ) {
    super(value);
  }
}
```

{% endcode %}