Logical operators AND, OR, NOT

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Quick Questions

Shade in the A or B circle for each question.

1. Which condition correctly checks that Age is between 0 and 120 inclusive?

A Age >= 0 OR Age <= 120

B Age >= 0 AND Age <= 120

2. Which condition is TRUE when Answer is outside the range 0 to 100?

A Answer < 0 OR Answer > 100

B Answer < 0 AND Answer > 100

3. Age is 25. What is the result of Age >= 0 AND Age <= 120?

A FALSE

B TRUE

4. Answer is 150. What is the result of Answer < 0 OR Answer > 100?

A TRUE

B FALSE

5. What does NOT do to a condition?

A It reverses TRUE to FALSE and FALSE to TRUE

B It makes both parts of the condition have to be true

Match the Pairs

Draw a line connecting each item on the left to its match on the right.

Left column		Right column
1Age >= 0 AND Age <= 120		AReverses the condition: true when Score is anything except 50
2NOT (Score = 50)		BAND is used where OR is needed. No number can be below 0 and above 100 at the same time, so the condition is never true. It should be Answer < 0 OR Answer > 100.
3OR is true when at least one condition is true, so it can catch a value outside a range		C(Age < 13 OR Age > 19) AND Member = TRUE
4Brackets make clear which conditions are combined first in a complex condition		DOR is used where AND is needed. Every number is at least 0 or at most 120, so invalid ages like -5 or 200 still pass. It should be Age >= 0 AND Age <= 120.
5IF Age >= 0 OR Age <= 120 THEN		EAnswer < 0 OR Answer > 100
6IF Answer < 0 AND Answer > 100 THEN		FTrue only when both conditions are true, so the age is inside the valid range 0 to 120

Definitions

AND OR NOT

Fill in the Blanks

Complete each line of code by filling in the missing parts.

IF Age >= 0 ___ Age <= 120 THEN OUTPUT "Age accepted" ENDIF

IF Answer < 0 __ Answer > 100 THEN OUTPUT "Out of range" ENDIF

IF ___ (Age >= 18) THEN OUTPUT "Under 18" ENDIF

WHILE NOT (Answer >= 0 ___ Answer <= 100) DO INPUT Answer ENDWHILE

Valid ← (Age >= 0) ___ (Age <= 120) OUTPUT Valid

Spot the Error

Shade in the letter of the line that contains an error.

Question 1

A INPUT Age

B IF Age >= 0 OR Age <= 120

C THEN

D OUTPUT "Valid"

E ENDIF

Question 2

A IF Answer < 0 AND Answer > 100

B THEN

C OUTPUT "Out of range"

D ENDIF

Question 3

A INPUT Age

B INPUT Paid

C IF Age >= 5 OR Paid = TRUE

D THEN

E OUTPUT "Enter"

F ENDIF

Question 4

A DECLARE Fail : BOOLEAN

B INPUT Mark

C Fail ← FALSE

D IF NOT (Mark < 50)

E THEN Fail ← TRUE

F ENDIF

Question 5

A DECLARE Age : INTEGER

B INPUT Age

C IF NOT Age < 0 OR Age > 120

D THEN

E OUTPUT "Accepted"

F ENDIF

Answer Key

Logical operators AND, OR, NOT

Section A: Quick Questions

B — Age >= 0 AND Age <= 120

A — Answer < 0 OR Answer > 100

B — TRUE

A — TRUE

A — It reverses TRUE to FALSE and FALSE to TRUE

Section B: Match the Pairs

Age >= 0 AND Age <= 120 → True only when both conditions are true, so the age is inside the valid range 0 to 120

NOT (Score = 50) → Reverses the condition: true when Score is anything except 50

OR is true when at least one condition is true, so it can catch a value outside a range → Answer < 0 OR Answer > 100

Brackets make clear which conditions are combined first in a complex condition → (Age < 13 OR Age > 19) AND Member = TRUE

IF Age >= 0 OR Age <= 120 THEN → OR is used where AND is needed. Every number is at least 0 or at most 120, so invalid ages like -5 or 200 still pass. It should be Age >= 0 AND Age <= 120.

IF Answer < 0 AND Answer > 100 THEN → AND is used where OR is needed. No number can be below 0 and above 100 at the same time, so the condition is never true. It should be Answer < 0 OR Answer > 100.

Section C: Definitions

AND OR NOT — Logical operators that combine BOOLEAN conditions: AND needs both true, OR needs at least one true, NOT reverses a condition. Use brackets in complex ones, e.g. Age >= 0 AND Age <= 120.

Section D: Fill in the Blanks

IF Age >= 0 AND Age <= 120 THEN
   OUTPUT "Age accepted"
ENDIF

IF Answer < 0 OR Answer > 100 THEN
   OUTPUT "Out of range"
ENDIF

IF NOT (Age >= 18) THEN
   OUTPUT "Under 18"
ENDIF

WHILE NOT (Answer >= 0 AND Answer <= 100) DO
   INPUT Answer
ENDWHILE

Valid ← (Age >= 0) AND (Age <= 120)
OUTPUT Valid

Section E: Spot the Error

B — With OR, only one part has to be true, so every number passes (for example -5 is <= 120). A valid age must be >= 0 AND <= 120, so both parts must be true.

A — No number can be below 0 and above 100 at the same time, so AND is never true and bad answers are never caught. It should be OR, because only one part needs to be true.

C — Entry needs BOTH conditions to be true: old enough AND paid. With OR, someone aged 5 or over gets in without paying. It should use AND.

D — NOT reverses a condition. NOT (Mark < 50) is true when the mark is 50 or more, which is a pass, so Fail would be set wrongly. It should be NOT (Mark >= 50), which is true for marks below 50.

C — The brackets are missing, so NOT only reverses Age < 0 and the OR part is worked out separately. The whole condition needs brackets: NOT (Age < 0 OR Age > 120).