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Doorman's Code

Sent in by:
Stephanie of North Olmsted, OH

You're a spy and you have to get into a building where there's a secret meeting. But, the doorman won't let you in unless you give him a secret code.

## Materials Needed

• some mathematical pattern-finding logic

## Instructions

1. To figure out the secret code, you watch three men give the doorman the secret code.
2. The first man walks up to the door and the doorman says 10. The first man answers 5 and he gets in.
3. The second man walks up to the door and the doorman says 8. The second man answers 4 and he gets in.
4. The third man walks up to the door and the doorman says 4. The third man answers 2 and he gets in.
5. What's the code?
6. Here's another one for you to figure out. The first man walks up to the door and the doorman says 7. The first man answers 8 and he gets in.
7. The second man walks up to the door and the doorman says 6. The second man answers 6 and he gets in.
8. The third man walks up to the door and the doorman says 10. The third man answers 14 and he gets in.
9. What's the code?

Ready for the solutions to the puzzles above? In the first one, whatever the doorman says, you have to divide by 2 to get the answer. In the second one, you subtract 3 from whatever the doorman says and then you multiply by 2! It's really fun to make up codes and have your friends try to figure them out. Think about other codes the doorman might come up with and send your ideas to ZOOM. We'll publish a bunch right here!

Anna, age 7 of Avon Lake, OH wrote:
It beaped when somebutey came in. It was riley funny!

Hailey of Lake Of The Woods, VA wrote:
I did it to my best friend shes not really good at math like I am but she still got it.

Allie, age 7 of Lowell, MA wrote:
I'm really good at math. I made my own code. My parents don't let me do it on them. I did it on my sister. She wasn't really good but she still did it.

Febby, age 12 of Dumaguete, Phil. wrote:
When the doorman will say a number, you will divide it by 2.

Olivia, age 11 of Plano, TX wrote:
I knew the first answer, but I thought the second was: doormans number- 6 plus the number for instance, 7-6= 1+ 7=8, 6-6=0 6+0=6 10-6=4 4+10=14

Salman, age 11 of New York City, NY wrote:
The first one was very easy divide by two the second one was a little hard because you had to subtract by three and then multiply by two.

Usama, age 11 of Montreal, QC wrote:
It was hard. The first one was easy, it was what ever number he said was divided by 2. But the second one was hard because the patern was different. The other one had to multiply by 2 andthe last one is to subtract by 6.

Antonio, age 12 of Baltimore, MD wrote:
I found out that the first one was whatever the doorman said it was divide by 2 and the second one was multiply by 2 and subtract 6.

Joshua, age 13 of Cereco, NE wrote:
The first one was easy, it was what ever number he said was divided by 2. But the second one was hard because the patern was different.

Mary, age 11 of Orlando, FL wrote:
For the first one I got you divided the number in half for the second one I got added together the numbers equaled a multiple of three.

Catherine, age 13 of Cincinnati, OH wrote:
I found a different solution to the second doorman's code in the example. Doorman-7, Spy-8; Doorman-6, Spy-6; Doorman-10, Spy-14. Zoom's solution is: subtract 3, multiply by two. My solution is: multiply by 2, subtract 6.

Jinai, age 10 of New York, NY wrote:
Doorman- 7, Spy 21. Doorman-8, Spy-22. Doorman-9, Spy-100(???). The answer is: Doorman-n, Spy-n (three), which means n in base three.

Grace, age 7 of Burnt Hills, NY wrote:
I figerd out that you have to subbtract 10 and add 2. Thats how I figerd out the code.

Ankur, age 15 of Cheshire, CT wrote:
Doorman says 4, spy says 1 doorman says 9, spy says 2 doorman says 16, spy says 3 doorman says 25, spy says 4 TRICKY: Doorman says 200, spy says 10 doorman says 50, spy says 5 doorman says 72, spy says 6

Steven, age 10 of Long Beach, CA wrote:
Doorman- 9 1st person- 3 Doorman- 12 1st person- 4 1st Solution: divide the doorman's number by 3 Doorman- 11 2nd Person- 7 Doorman- 25 2nd person- 14 2nd Solution: Add 3 to the doorman's number and divide by 2.

Alexia, age 10 of Monongahela, PA wrote:
What I did, the doorman said an even number above 2 then you'd multiply by 2 and add 3.

Rachel, age 11 of Story City, IA wrote:
Each time it looked like the doorman says a number, and you have to divide it by 2, which gives you the answer. Taa-daah!!

Rebekah, age 13 of Lapel, IN wrote:
The doorman says five and the guy says four. The doorman says ten and the guy say three. The doorman says eleven and the guy says seven. What is the code? However many letters are in the word of the number.

Jennifer, age 12 of Cornwall, ON wrote:
For the first code it is SO simple! Its obvious that you divide the numbers by two.

Vivi, age 9 of Carmel, IN wrote:
I just divided the number by two. If it was 14 it would be 7, or if the doorman said 24 you would say 12 to get in.

Gary, age 10 of Southfield, MI wrote:
I found that whatever the Doorman says, divide it by 2 (ie. the doorman says 20 the answer is 10).

Vanessa, age 12 of Phoenix wrote:
The first man went up to the door and the doorman said 15 the man says 7. The second man went up to the door and the doorman said 32 and the man says 24. The thrid man went up to the door and the doorman said 26 the man says 18. What is the pattern? The pattern is subtract 10 then add 2.

Alicia, age 11 of Cupertino, CA wrote:
Doorman: 5, first man: 1. Doorman: 10, Second man: 2. Doorman: 15, Third man: 3.

Samantha, age 11 of Sherwood, OR wrote:
The doorman says 18 and you say 18. Then the doorman says 25 and you say 14. The code is you add the digets in the number together and multiply by 2.

T, age 12 of Waterbury, CT wrote:
The first code is half of the first number given.

Alexa, age 10 of Lower Burrell, PA wrote:
You divide the doorman's number by 2 and then multiply it by 3. EXAMPLE: doorman: 12 man:18 How: 12 divided by 2=6, 6x3=18, 18 is the correct answer.

Carson, age 10 of Cleveland, OK wrote:
The Doorman said 24 and I said 8 because 8 is the sqare root of 24.

Sarah, age 14 of Winder, GA wrote:
The doorman say's 3 the first man says 9 and goes in. The doorman says 6 the second man says 24 and goes in. The doorman says 8 the third man says 40 and goes in. What's the code?

not yet implemented