if / else: app rules — App development for students

Developer's tip

Test, then choose — “if the test is true run the if part, otherwise the else part”

1. if (test) { A } else { B }: A runs when the test is true, B when it is false.
2. else if: check from the top; the first true test wins and the rest are skipped.
3. >= includes the number itself; > does not. === tests “is equal to”.

Use it for: Age checks, scores and badges, discounts, battery and PIN rules in your apps.

Worked example: 🔀 Which badge does this quiz app show?
let marks = 24;
if (marks >= 80) {
  show("Gold");
} else if (marks >= 50) {
  show("Silver");
} else {
  show("Bronze");
} → Bronze

✏️ Practice

Work it out in your head or on paper, type the answer and press Check. Stuck? Press “Show me how”.

🏁 Lesson 18 test

20 questions. Check each answer, then go to the next one. Get 16 or more right to pass.

🏅 Sign in with Google to earn the 🚦 App Rule Maker badge when you pass — and a certificate when you finish all 8 lessons of Part 3 · Logic and Building. You can still take the test without signing in.

🖨️ App Dev Worksheet: If Else Rules

• Worksheet set 1 (PDF)
• Worksheet set 2 (PDF)
• Worksheet set 3 (PDF)