---
title: "formTruncatingRemainder(dividingBy:)"
framework: swift
role: symbol
role_heading: Instance Method
path: "swift/float80/formtruncatingremainder(dividingby:)"
---

# formTruncatingRemainder(dividingBy:)

Replaces this value with the remainder of itself divided by the given value using truncating division.

## Declaration

```swift
mutating func formTruncatingRemainder(dividingBy other: Float80)
```

## Parameters

- `other`: The value to use when dividing this value.

## Discussion

Discussion Performing truncating division with floating-point values results in a truncated integer quotient and a remainder. For values x and y and their truncated integer quotient q, the remainder r satisfies x == y * q + r. The following example calculates the truncating remainder of dividing 8.625 by 0.75: var x = 8.625 print(x / 0.75) // Prints "11.5"

let q = (x / 0.75).rounded(.towardZero) // q == 11.0 x.formTruncatingRemainder(dividingBy: 0.75) // x == 0.375

let x1 = 0.75 * q + x // x1 == 8.625 If this value and other are both finite numbers, the truncating remainder has the same sign as this value and is strictly smaller in magnitude than other. The formTruncatingRemainder(dividingBy:) method is always exact.