Coding classes in Greater Manchester

The museum tells us what the Baby's first program did: find the highest factor of a number, and by August 1948 it could do so for two to the power eighteen, which is 262,144. The obvious method is to start just below the number and count down, testing each candidate until one divides exactly. The learner writes that in a few lines of Python and gets 131,072, the museum's answer. Then they add a counter, and it reports that the search tested 131,072 candidates before it stopped.

Now the better question. The highest factor of a number is the number divided by its smallest factor, other than 1. So instead of counting down from the top, count up from 2. For 262,144 the very first test succeeds, because the number is even, and 262,144 divided by 2 is 131,072. Same answer, one test instead of 131,072. Nothing about the computer changed. The only thing that changed was the question.

The last row shows why good programmers always look for the worst case. For a prime number, counting down never finds a factor until it reaches 1, testing 262,138 candidates. Counting up can stop much earlier: if no number up to the square root divides it, nothing above the square root can either, so it gives up after 510 tests. The clever method is fast on easy inputs and still fast on the hardest ones, which is the property that matters when you do not choose the input yourself.

So a Greater Manchester teenager should still learn to code in 2026, in the county where the first stored program ran, to be the person who asks the better question. The longer argument is in why teenagers should still learn to code in 2026.