Convert the octal number 143₈ to its decimal (base-10) value.

Introduction / Context:Octal (base-8) numbers arise historically from grouping binary digits in sets of three. Converting octal to decimal reinforces positional-value understanding and prepares you for quick binary conversions as well.

Given Data / Assumptions:

• Octal input: 143₈.
• Octal digits range from 0 to 7.
• Place values: 8^0, 8^1, 8^2, ...

Concept / Approach:

• Use positional expansion: abc₈ = a8^2 + b8^1 + c8^0.
• Compute powers: 8^2 = 64, 8^1 = 8, 8^0 = 1.

Step-by-Step Solution:

Verification / Alternative check:

Why Other Options Are Wrong:

• 90₁₀, 971₁₀, 107₁₀: Do not match the positional expansion result.
• None of the above: Incorrect because 99₁₀ is correct.

Common Pitfalls:

• Accidentally treating octal digits as decimal during expansion.
• Miscomputing 8^2 or 8^1, which skews the final sum.

Final Answer: