This activity touches on several key ideas in computing.
One is that dividing big problems in half, then half again, and so on, makes them very small very quickly.
With 100 possible values, only 7 questions are ever needed to narrow down to the secret value if you use the right strategy.
In Arnold’s challenges students can experiment with guessing numbers from 1 to 1000 - it looks like it would be 10 times as hard, but it only needs three more questions!
Every time the range doubles in size, you only need one more question to guess a number in the range.
In fact, you could guess a number from 1 to a million using only 20 questions - it doesn’t take that long, although you might want to use a calculator to half the range each time.
This approach to narrowing down towards a solution is behind some very fast computer algorithms.

Another idea in the activity is that you can achieve a lot with only “binary” yes/no decisions.
You might think that you need to check if the final value is equal, but you can know for use only by using “greater than or equal”.
Decisions that have two outcomes (often referred to as true or false) are the basis of “Boolean logic”, which is one of the key ideas used in the design of digital devices.

Add inside the computer section.
Add inside the computer section.
