Arithmetic expansion $(( )) in Bash Scripting - Practice Problems & Coding Challenges

Challenge - 5 Problems

💻 Command Output

intermediate

Output of arithmetic expansion with mixed operators

What is the output of this bash command?

echo $((3 + 4 * 2 - 1))

Bash Scripting

echo $((3 + 4 * 2 - 1))

A 10

B 14

C 12

D 9

💡 Hint

Remember the order of operations: multiplication before addition and subtraction.

Multiplication happens first: 4 * 2 = 8. Then addition and subtraction: 3 + 8 - 1 = 10. So output is 10.

💻 Command Output

intermediate

Result of arithmetic expansion with variable substitution

Given x=5, what is the output of this command?

x=5
echo $((x * 3 + 2))

Bash Scripting

x=5
echo $((x * 3 + 2))

A 21

B 15

C 17

D 11

💡 Hint

Substitute x with 5 and calculate.

x=5, so 5 * 3 + 2 = 15 + 2 = 17.

📝 Syntax

advanced

Identify the syntax error in arithmetic expansion

Which option contains a syntax error in arithmetic expansion?

A echo $((3 + ))

B echo $((10 / 2))

C echo $((7 - 4))

D echo $((3 + 5))

💡 Hint

Look for incomplete expressions inside $(( )).

Option A has an incomplete expression '3 + ' which causes a syntax error.

🔧 Debug

advanced

Why does this arithmetic expansion output 0?

Given a=3 and b=5, what is the output of this command and why?

a=3
b=5
echo $((a / b))

Bash Scripting

a=3
b=5
echo $((a / b))

A 0 because division by zero returns zero

B 0 because b is zero

C 0 because variables are not expanded inside $(( ))

D 0 because integer division truncates the decimal part

💡 Hint

Think about how bash handles division with integers.

Bash arithmetic expansion uses integer math, so 3/5 is 0.6 but truncated to 0.

🚀 Application

expert

Calculate factorial using arithmetic expansion in a loop

What is the output of this bash script?

n=4
fact=1
for ((i=1; i<=n; i++)); do
  fact=$((fact * i))
done
echo $fact

Bash Scripting

n=4
fact=1
for ((i=1; i<=n; i++)); do
  fact=$((fact * i))
done
echo $fact

A 10

B 24

C 1

D 120

💡 Hint

Factorial of 4 is 4*3*2*1.

The loop multiplies fact by i from 1 to 4: 1*1=1, 1*2=2, 2*3=6, 6*4=24.