Logical operator OR

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Quick Questions

Shade in the A or B circle for each question.

1. Day ← "Sun". What is the result of: Day = "Sat" OR Day = "Sun"

A TRUE, because the second condition is TRUE

B FALSE, because the first condition is FALSE

2. Which statement about OR is correct?

A It is only FALSE when both conditions are FALSE

B It is only TRUE when both conditions are TRUE

3. Which line correctly checks for a weekend day?

A IF Day = "Sat" OR "Sun" THEN

B IF Day = "Sat" OR Day = "Sun" THEN

4. Mark ← 120. What is the result of: Mark < 0 OR Mark > 100

A TRUE, because Mark > 100 is TRUE

B FALSE, because Mark < 0 is FALSE

5. Which condition is TRUE for a value outside the range 1 to 10?

A Num < 1 AND Num > 10

B Num < 1 OR Num > 10

Match the Pairs

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

Left column		Right column
1Day = "Sat" OR Day = "Sun"		ATRUE if the day is Saturday or Sunday (the weekend)
2Mark < 0 OR Mark > 100		BAND is used where OR is needed. No score can be below 0 and above 100 at once, so the condition is never TRUE. It should be OR.
3OR is only FALSE when both conditions are FALSE		Cx <- 10 IF x > 5 OR x > 8 THEN
4OR is still TRUE when both conditions are TRUE		DTRUE if the mark is outside the valid range 0 to 100
5IF Day = "Sat" OR "Sun" THEN		EIF Age < 5 OR Age > 65 THEN
6IF Score < 0 AND Score > 100 THEN		FEach side of OR must be a full condition. "Sun" on its own is not a condition. It should be Day = "Sat" OR Day = "Sun".

Definitions

Fill in the Blanks

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

IF Day = "Sat" __ Day = "Sun" THEN OUTPUT "Weekend" ENDIF

IF Mark < 0 __ Mark > 100 THEN OUTPUT "Invalid mark" ENDIF

IF Age < 5 OR Age _ 65 THEN OUTPUT "Free ticket" ENDIF

Wet <- TRUE Cold <- TRUE OUTPUT Wet __ Cold

IF Letter = "a" OR Letter = "e" ____ OUTPUT "Vowel" ENDIF

Spot the Error

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

Question 1

A DECLARE Day : STRING

B OUTPUT "Enter the day"

C INPUT Day

D IF Day = "Sat" AND Day = "Sun"

E THEN OUTPUT "Weekend"

F ENDIF

Question 2

A INPUT Mark

B IF Mark > 0 OR Mark < 100

C THEN OUTPUT "Invalid"

D ENDIF

Question 3

A Age ← 15

B Member ← TRUE

C IF Age < 16 OR Member == TRUE

D THEN OUTPUT "Cheap entry"

E ENDIF

Question 4

A DECLARE Ans : CHAR

B INPUT Ans

C IF Ans = "Y" OR "y"

D THEN OUTPUT "Yes"

E ENDIF

Question 5

A INPUT Temp

B OUTPUT "Checking"

C IF Temp < 5 OR Temp < 35

D THEN OUTPUT "Extreme"

E ELSE OUTPUT "Normal"

F ENDIF

Answer Key

Logical operator OR

Section A: Quick Questions

A — TRUE, because the second condition is TRUE

A — It is only FALSE when both conditions are FALSE

B — IF Day = "Sat" OR Day = "Sun" THEN

A — TRUE, because Mark > 100 is TRUE

B — Num < 1 OR Num > 10

Section B: Match the Pairs

Day = "Sat" OR Day = "Sun" → TRUE if the day is Saturday or Sunday (the weekend)

Mark < 0 OR Mark > 100 → TRUE if the mark is outside the valid range 0 to 100

OR is only FALSE when both conditions are FALSE → IF Age < 5 OR Age > 65 THEN

OR is still TRUE when both conditions are TRUE → x <- 10 IF x > 5 OR x > 8 THEN

IF Day = "Sat" OR "Sun" THEN → Each side of OR must be a full condition. "Sun" on its own is not a condition. It should be Day = "Sat" OR Day = "Sun".

IF Score < 0 AND Score > 100 THEN → AND is used where OR is needed. No score can be below 0 and above 100 at once, so the condition is never TRUE. It should be OR.

Section C: Definitions

OR — Joins two conditions. The result is TRUE when at least one condition is TRUE, e.g. Day = "Sat" OR Day = "Sun". It is only FALSE when both conditions are FALSE.

Section D: Fill in the Blanks

IF Day = "Sat" OR Day = "Sun" THEN
  OUTPUT "Weekend"
ENDIF

IF Mark < 0 OR Mark > 100 THEN
  OUTPUT "Invalid mark"
ENDIF

IF Age < 5 OR Age > 65 THEN
  OUTPUT "Free ticket"
ENDIF

Wet <- TRUE
Cold <- TRUE
OUTPUT Wet OR Cold

IF Letter = "a" OR Letter = "e" THEN
  OUTPUT "Vowel"
ENDIF

Section E: Spot the Error

D — Day cannot be both "Sat" and "Sun" at once, so AND is never TRUE. OR is needed: IF Day = "Sat" OR Day = "Sun".

B — The conditions are the wrong way round. Every number is above 0 or below 100, so every mark would be invalid. It should be IF Mark < 0 OR Mark > 100.

C — Cambridge pseudocode compares with a single =, not ==. The line should be IF Age < 16 OR Member = TRUE. Both conditions are TRUE here and OR is still TRUE.

C — OR joins two full conditions. "y" on its own is not a condition. It should be IF Ans = "Y" OR Ans = "y".

C — The second condition should test for values above the range. Temp < 35 is TRUE for 20, so a normal temperature would be Extreme. It should be Temp > 35.