Logical operator ||
Name:
Date:
Class:
A
Quick Questions
Shade in the A or B circle for each question.
1. If day is "Sat", what does day === "Sat" || day === "Sun" give?
2. Which result does true || false give?
3. When is a || b false?
4. Which line correctly checks if day is Sat or Sun?
5. If day is "Wed", what does day === "Sat" || day === "Sun" give?
B
Match the Pairs
Draw a line connecting each item on the left to its match on the right.
| Left column | Right column | |
|---|---|---|
| 1day === "Sat" || day === "Sun" | Ascore === 0 || score === 100 | |
| 2false || false | BGives false, because || is false only when both sides are false | |
| 3Either one of two conditions is enough to make the whole condition true | Cconsole.log(5 > 10 || 2 > 8); | |
| 4|| gives false only when both conditions are false | DOR is written with two vertical bars ||. A single | is a different operator. | |
| 5if (day === "Sat" || "Sun") { | EThe right side of || is just the text "Sun", not a comparison. Each side of || needs its own full condition. | |
| 6if (day === "Sat" | day === "Sun") { | FTrue when the day is Saturday or Sunday, so it is true on the weekend |
C
Definitions
logical OR
D
Fill in the Blanks
Complete each line of code by filling in the missing parts.
1.
let off = day === "Sat" __ day === "Sun";
2.
__ (day === "Sat" || day === "Sun") {
console.log("Weekend!");
}
3.
let hasPass = false;
let hasTicket = true;
let canEnter = hasPass __ hasTicket;
4.
if (score < 0 || score _ 100) {
console.log("Invalid");
}
5.
let isSat = day === "Sat";
let isSun = day === "Sun";
let off = isSat || _____;
E
Spot the Error
Shade in the letter of the line that contains an error.
Question 1
A
let day = "Sun";
B
let sat = day === "Sat";
C
let sun = day === "Sun";
D
console.log(sat | sun);
Question 2
A
let temp = 38;
B
if (temp < 0 || > 35) {
C
console.log("Extreme");
D
}
Question 3
A
let age = 9;
B
if (age < 5 or age > 65) {
C
console.log("Free entry");
D
}
Question 4
A
let hasPen = false;
B
let hasPencil = true;
C
if hasPen || hasPencil {
D
console.log("Can write");
E
}
Question 5
A
let isRaining = True;
B
let isCold = false;
C
if (isRaining || isCold) {
D
console.log("Take a jacket");
E
}
Answer Key
Logical operator ||
Section A: Quick Questions
Q1
B — true
Q2
B — true
Q3
A — Only when both a and b are false
Q4
A — day === "Sat" || day === "Sun"
Q5
A — false
Section B: Match the Pairs
Q1
day === "Sat" || day === "Sun" → True when the day is Saturday or Sunday, so it is true on the weekend
Q2
false || false → Gives false, because || is false only when both sides are false
Q3
Either one of two conditions is enough to make the whole condition true → score === 0 || score === 100
Q4
|| gives false only when both conditions are false → console.log(5 > 10 || 2 > 8);
Q5
if (day === "Sat" || "Sun") { → The right side of || is just the text "Sun", not a comparison. Each side of || needs its own full condition.
Q6
if (day === "Sat" | day === "Sun") { → OR is written with two vertical bars ||. A single | is a different operator.
Section C: Definitions
Q1
logical OR — Logical OR joins two conditions. It is true when at least one is true, and false only when both are false. Example: day === 'Sat' OR day === 'Sun' is true on a weekend.Section D: Fill in the Blanks
Q1
let off = day === "Sat" || day === "Sun";Q2
if (day === "Sat" || day === "Sun") {
console.log("Weekend!");
}Q3
let hasPass = false;
let hasTicket = true;
let canEnter = hasPass || hasTicket;Q4
if (score < 0 || score > 100) {
console.log("Invalid");
}Q5
let isSat = day === "Sat";
let isSun = day === "Sun";
let off = isSat || isSun;Section E: Spot the Error
Q1
D — A single | is a different (bitwise) operator. OR needs two bars, so it should be console.log(sat || sun);
Q2
B — Each side of || must be a full condition. The right side is missing temp, so it should be temp > 35.
Q3
B — JavaScript does not use the word or. The OR operator is written ||, so it should be age < 5 || age > 65.
Q4
C — The condition of an if statement must be inside brackets. It should be if (hasPen || hasPencil) {
Q5
A — Boolean values are written in lowercase in JavaScript. True causes an error, so it should be true.