Use The Math Package

package main

import (
			"fmt"
)

func main() {
		//Go compiler recognises these and then implicitly sets the types of the variables to int
		i1, i2, i3 := 12, 45, 68
		// We now add the values together:
		intSum := i1 + i2 + i3
		fmt.Println("Integer sum:", intSum)
}

When you want to declare more than 1 variable of the same type, you can do it all in a single statement.
The output of intSum above would be 125.
To add floating numbers together, we can perform the following: ``` package main

import ( “fmt” )

func main() { //Go compiler recognises these and then implicitly sets the types of the variables to int i1, i2, i3 := 12, 45, 68 // We now add the values together: intSum := i1 + i2 + i3 fmt.Println(“Integer sum:”, intSum)

	f1, f2, f3 := 23.5, 65.1, 76.3
	floatSum := f1 + f2 + f3
	fmt.Println("Float sum:", floatSum) } ``` * Running the above would output the following: ``` Float sum: 164.8999999999998 ``` * We see the above, because floating values in Go are stored in binary. Therefore simple mathematical operations don't always provide the precision you expect.
* The `math/big` package can help accomplish this. * We can make this more precise with the `math` package: ``` package main

import ( “fmt” “math” )

	f1, f2, f3 := 23.5, 65.1, 76.3
	floatSum := f1 + f2 + f3
	fmt.Println("Float sum:", floatSum)

	//We reassign the value of floatSum like below. We are not using the := operator, because the floatSum variable in this case has already been initialised.
	floatSum = math.Round(floatSum)
fmt.Println("The sum is now", floatSum) } ``` * Running the above then shows the `floatSum` as `165` and rounds to an integer. * We however want to round to the nearest 2 decimals. ``` package main

import ( “fmt” “math” )

	f1, f2, f3 := 23.5, 65.1, 76.3
	floatSum := f1 + f2 + f3
	fmt.Println("Float sum:", floatSum)

	//We reassign the value of floatSum like below. We are not using the := operator, because the floatSum variable in this case has already been initialised.
	floatSum = math.Round(floatSum*100) / 100
fmt.Println("The sum is now", floatSum) } ``` * The output we then see is the expected of `164.9`. * Another tool from the `math` package with useful constants. ``` package main

import ( “fmt” “math” )

	f1, f2, f3 := 23.5, 65.1, 76.3
	floatSum := f1 + f2 + f3
	fmt.Println("Float sum:", floatSum)

	//We reassign the value of floatSum like below. We are not using the := operator, because the floatSum variable in this case has already been initialised.
	floatSum = math.Round(floatSum*100) / 100
fmt.Println("The sum is now", floatSum)

  circleRadius := 15.5
  // The "circleRadius * 2" is the diameter. The constant is "math.Pi"
  circumference := circleRadius * 2 * math.Pi
  // We now need to do formatting on the number with:
  // The %.2f is a floating number with two digits after the decimal
  fmt.Printf("Circumference: %.2f", circumference) } ``` * The output code would then output the following: ``` Circumference: 97.39 ```