Inside reduce: a Nested gcd and the Branch That Returns an int

Why does one `elif` branch handing back an int instead of a Fraction quietly break multiplication for the whole class?

Finger exercises

Short drills on what this video just taught. Write the code, run the checks, and reveal the answer only if you are stuck.

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Exercise 1 of 5

Trace the tuple assignment inside gcd

The helper from the lecture is about to run on n = 84 and d = 36:

while d != 0:
    (d, n) = (n%d, d)
return n

Work the loop through on paper. Assign to gcd_trace a list holding the pair (n, d) as it stands after each tuple assignment, in order — one tuple per pass of the loop, and nothing else in the list.

# The (n, d) pair after each pass, starting from n = 84 and d = 36.
gcd_trace = ...  # your code here

# The (n, d) pair after each pass, starting from n = 84 and d = 36.
gcd_trace = ...  # your code here

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`gcd_trace` is a list of two-item tuples

records the state after each assignment, not the starting pair

holds one pair per pass of the loop

each pair is the state the pass left behind

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