Name
Date
DIRECTIONS: Deal twenty cards face up in a row, shuffled. Find the seven of hearts. Count every card you look at.
Count looks, not seconds.
| Finding one card among twenty | Looks I needed |
|---|
| 1. Shuffled — first try | |
| 2. Shuffled — a different card | |
| 3. Shuffled — a card that is not there at all | |
| 4. Now put them in order first, then find one by halving | |
Row 3: a missing card costs every look. Sorted, it costs 5.
Sorting isn't free, though. Page 2 asks when it pays.
- You will look up exactly one card and never touch the pile again. Is it worth sorting first? Say why.
- You will look up a card a hundred times over the next week. Now is it worth sorting? Say what changed — the sorting did not get cheaper.
- A phone book is sorted and nobody thinks about it. Say what job the sorting is doing, and who paid for it.
- Give one thing in your house that is sorted so it can be searched, and one that is not sorted because nobody searches it.