Recipe Scaler

Go's arithmetic operators (+, -, *, /) look exactly like the math you already know, with one catch: when both operands are integers, / throws away the remainder instead of rounding. 7 / 2 is 3, not 3.5 and not 4. That single fact shapes how you design programs that split totals into equal shares — the result is always a little less than the mathematically exact answer, and any leftover just vanishes.

Worked example

Here's the same scaling logic applied to a bigger batch:

package main

import "fmt"

func main() {
	servings := 5
	totalFlourGrams := 400
	totalEggs := 15

	flourPerServing := totalFlourGrams / servings
	eggsPerServing := totalEggs / servings

	doubleServings := servings * 2
	doubleFlour := flourPerServing * doubleServings

	fmt.Println("Recipe scaler (per serving):")
	fmt.Printf("Flour: %d grams\n", flourPerServing)
	fmt.Printf("Eggs: %d\n", eggsPerServing)
	fmt.Printf("Doubled batch serves %d, needs %d grams flour\n", doubleServings, doubleFlour)
}

Recipe scaler (per serving):
Flour: 80 grams
Eggs: 3
Doubled batch serves 10, needs 800 grams flour

Here 400 / 5 divides evenly, so there's no truncation to notice — but in the exercise below, 250 grams split four ways doesn't divide evenly, and that's exactly the case worth paying attention to.

Your turn

The starter program tries to compute flour and eggs per serving and then figure out what a doubled batch needs, but two of the arithmetic operators don't match what their variable names promise. Read each marked line, decide what operation the comment describes, and swap in the right operator.

If something goes wrong

If your flour-per-serving number looks too big, you probably still have multiplication where division belongs. If the doubled batch numbers look identical to the single batch, check that doubleServings is actually double — a leftover + 2 will only add two servings, not double them. And if you're ever unsure why a division result looks lower than you expected, that's the truncation at work: Go integer division always rounds down toward zero for positive numbers.