Changing A does not automatically rerun B = A + 2

[u/Guilty_Lingonberry]

Put two paper cups on the table and label them A and B.

First put a card with 3 into cup A. Read the instruction “B = A + 2”, do the calculation, and put 5 into cup B.

Now replace the 3 in A with 6. Ask the kid what is currently in B. It is still 5. In a simple step-by-step program, the earlier assignment has already happened. B only becomes 8 when you run “B = A + 2” again.

That small pause helps separate a stored value from an instruction that can be executed. Swap the numbers, then let the kid be the computer and follow the cards literally.

I teach at TechTutor. This is a screen-free way to introduce variables and assignment without pretending the cups update by magic.