FAQ: Binary Numbering System - Adding Binary Numbers

This community-built FAQ covers the “Adding Binary Numbers” exercise from the lesson “Binary Numbering System”.

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This exercise can be found in the following Codecademy content:

(Beta) CS104: Computer Architecture

FAQs on the exercise Adding Binary Numbers

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Solution error…


101011 => 4310
010010 => 1810
111101 => 6110


@catower, is this something you might be able to address?

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Hate to bug you again, @catower. Next lesson over, subtracting binary numbers

Create another variable, answer2 , and set it equal to the result of 10010 2 - 11011 2.

Learners haven’t been advised how to work with negative numbers, or that the MSB is the sign bit. Should the larger value be on the left side of the operator for this exercise?

>>> bin(int('0b10010', 2) - int('0b11011', 2))
>>> bin(int('0b11011', 2) - int('0b10010', 2))


Yeah, I know there is no negative sign in Binary. Was just testing the exercise checker before I looked at the solution.


If we confuse learners on this stuff, they’re never going to make it through two’s complement.

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@catower, looks like the answer2 has been corrected in the solution code, but you still cannot pass the SCT for instruction #2 unless you provide the incorrect answer shown in @mtf’s screenshot.

Correct answer fails:

Solution shows correct answer, but it fails the SCT.

Incorrect answer passes the SCT.

Hey this should be working correctly since you’ve posted.

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Tried it again just now. The correct answer still fails the SCT.

EDIT: Never mind. Just reloaded the page, and it is fixed. Thanks, @catower!

1 Like