JavaScript lesson 8: Comparisons, true and false
US version. US grades and US spelling. · UK version of this lesson
A comparison gives true or false. These two values are called booleans. A complete 40-minute JavaScript lesson for beginners (Grades 7–8), from Unit 4: Decisions. It runs right here in your browser – nothing to install.
- Time
- 40 minutes + 20 min homework
- Grade
- Grades 7–8 (ages 12–13)
- You need
- A computer or tablet, paper and a pencil
- Graded
- Instantly, with explanations
For parents: how to use this lesson
You don't need to know JavaScript yourself. The lesson explains each step on screen, the way Mr Babbage, our Head of Computing, likes it: a worked example first, then a go for your child. Code questions run your child's program in the browser – graded straight away.
- Read what your child will learn together.
- Press Start the lesson below. Sit with your child for the teaching and the worked example (about 16 minutes): ask them to say what each line does.
- Let them do the practice on their own. When code goes wrong, the error message is a clue – let them read it out and try again before you help.
- Finish with the talk question: Why do programmers prefer === to ==?
Watch out for
"5" === 5is true. === checks the type too."10" < "9"is false. As text, "1" comes before "9".
Miss Lovelace's tip for home: ask your child to explain one line of their program to you in their own words. If they can explain it, they understand it – and every error message is a clue, not a failure.
What your child will learn
Learning goal: compare values with ===, !==, <, >, <= and >=.
Success looks like
- I can compare values with
===,!==,<,>,<=and>=. - I can explain why
"5" === 5is false. - I can predict comparisons of text.
Key words
boolean · true · false · comparison · === · !==
What to have ready
- A device with a web browser (the code runs in the browser – nothing to install)
- Paper for tracing
- A keyboard helps for typing code (a tablet or phone works too)
The big ideas (for the adult)
A comparison gives true or false. These two values are called booleans.
=== is true when two values are the same AND the same type, so "5" === 5 is false. == converts types first, which can surprise you – Classfern always uses === and !==.
Two strings are compared letter by letter, so "10" < "9" is true. Turn text into numbers before comparing amounts.
Worked example – see it
console.log(5 < 19)
It prints:
true
The lesson, step by step
| Part | Time | How it is checked |
|---|---|---|
| Starter | 5 min | Graded by Classfern |
| Teaching input | 8 min | Read, watch and talk |
| See it, then predict | 8 min | Graded by Classfern |
| Put it in order, write it, fix it | 14 min | Graded by Classfern |
| Closure and exit ticket | 5 min | Graded by Classfern + self-check |
The lesson
It runs here on the page. No sign-up and no names – progress is kept only in this browser. Each visit picks a new mix of questions.
Homework
20 minutes: 7 questions – predict what code prints, write or fix a short program, and check the key ideas – then a short reflection. New questions every time, all graded instantly.
Practice tests
Curriculum
CSTA K–12 Computer Science Standards (2017), grades 6–8: 2-AP-12 – Design and iteratively develop programs with control structures incl. nested loops and compound conditionals.
The standard codes are CSTA's; the descriptions are our own words.
Our lessons and questions are our own. They are not written or endorsed by any government department, testing agency or exam board. JavaScript is a trademark or registered trademark of Oracle Corporation in the U.S. and other countries; Classfern is not affiliated with or endorsed by it.