-
Notifications
You must be signed in to change notification settings - Fork 1
New issue
Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.
By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.
Already on GitHub? Sign in to your account
Grace - Added more problems #73
Changes from all commits
195565e
f211435
4c7ba4b
a9b0c3f
ae56ba8
4fb7125
512eb2f
a28a80f
7e35a55
52bbcc8
b9c4cc0
19a7c46
fd68240
03f8cf1
5dd5ae8
aa665ff
ea91e95
6146c3d
24e37e7
File filter
Filter by extension
Conversations
Jump to
Diff view
Diff view
There are no files selected for viewing
Original file line number | Diff line number | Diff line change |
---|---|---|
@@ -0,0 +1,27 @@ | ||
# Counting Chickens | ||
|
||
## Introduction | ||
|
||
This activity looks at the interesting concept of having a circle with n points on its perimeter and what happens when you joint those points up. | ||
|
||
Three examples are given on the question sheet so students can see how to visualize the problems. The activity questions rely on students being able to develop on these primary examples to solve more complicated cases. The extension looks at spotting a pattern and developing a rule. | ||
|
||
It is advisable that students try drawing out each case. It should be noted that the use of colours can be a | ||
way for students to picture the different regions more easily. | ||
|
||
## Solution | ||
|
||
![](../../images/counting-chickens-2.png) | ||
|
||
## Extension | ||
|
||
Is there a pattern between the number of fence posts and the maximum number of chickens that can be kept? | ||
|
||
Hint: Fill out this table (some of it has been filled out for you) | ||
|
||
![](../../images/counting-chickens-3.png) | ||
|
||
Using Pascal’s triangle, what will happen if you add the numbers to the left of the line in each row? Can | ||
you spot the pattern now? Can you explain this strange pattern? | ||
|
||
![](../../images/counting-chickens-4.png) |
Original file line number | Diff line number | Diff line change |
---|---|---|
@@ -0,0 +1,32 @@ | ||
# Frog Party | ||
|
||
## Introduction | ||
|
||
This is a really fun problem, and can be used to build many much harder problems. It is important when starting to problem to make sure the rules are clear. You might want to do this by showing examples of moves which are and are not allowed, using coins on top of pieces of paper or similar. | ||
|
||
## Solution | ||
|
||
There are many ways to solve this, and it is possible to have a party on every single lily pad. Two examples are given below, however you should ask students to also share their solutions | ||
|
||
![](../../images/frog-party-3.png) | ||
|
||
## Extension | ||
|
||
There are lots of ways you can make this problem more challenging and interesting, | ||
which include: | ||
|
||
- Add more lily pads, is it still possible with 6, 10 or N? | ||
There was a problem hiding this comment. Choose a reason for hiding this commentThe reason will be displayed to describe this comment to others. Learn more. Can we format this as a table to keep images on the right and text on the left? |
||
|
||
![](../../images/frog-party-4.png) | ||
|
||
- Choose one of the frogs to be the Queen frog, who must be at the top of the | ||
party | ||
|
||
![](../../images/frog-party-5.png) | ||
|
||
- Swap one of the frogs for a lazy toad, who refuses to move. Is it still possible? | ||
|
||
![](../../images/frog-party-6.png) | ||
|
||
Note, the strategy used in the second solution of working from the inside out also works | ||
for any number of lily pads! |
Original file line number | Diff line number | Diff line change |
---|---|---|
@@ -0,0 +1,37 @@ | ||
# Locks and Keys | ||
|
||
## Introduction | ||
|
||
This problem is not specified very precisely, and in this case it is intentional. The aim of this problem is to work with assumptions. The problem has different solutions under different assumptions, and it might be | ||
easy or even impossible depending on the assumptions. For example, if we assume that the messenger can break the box or the lock, then the problem is impossible (and somewhat pointless). | ||
|
||
There is no right or wrong solution because there is no right or wrong set of assumptions. However, if we specify our assumptions clearly, then for the given set of assumptions any solution is either right or wrong. | ||
The facilitator should encourage students to decide on what should be allowed or not so that the problem is not solved too easily or made impossible. | ||
|
||
This activity involves lots of discussion between groups. It could help to have paper cutouts of locks, keys and boxes so students can demonstrate rather than only explain. You should encourage students to demonstrate their solutions, and to challenge each other to see if they can find a way to intercept. | ||
|
||
## Solution | ||
|
||
There’s are lots of different strategies that could be tested and argued, here we will only outline a few possibilities, it is up to the students and facilitator to decide if their own solutions work or not. | ||
|
||
We will start with a few assumptions: | ||
|
||
1. The messenger cannot break the box or the lock. | ||
|
||
2. The messenger cannot make copies of keys. | ||
|
||
**Case 1:** Alice locks the box and sends it to Bob. Bob sends the messenger back to Alice. Alice now gives the messenger the key to send it to Bob. The messenger gives the key to Bob and Bob unlocks the box. | ||
|
||
**Intercept:** The messenger only pretends to deliver the box to Bob, but instead keeps it. He then returns it back to Alice and obtains the key to unlock the box and read the message. | ||
|
||
**Case 2:** Alice sends the key using a different messenger than for the box. | ||
|
||
**Intercept:** The messengers collaborate. You would need to decide in the rules whether this would be possible. | ||
|
||
**Case 3:** Alice locks the box with her lock and sends it to Bob. Bob attaches his own lock and sends it back.Alice takes her lock off the box and sends it back again. Finally, Bob takes his own lock off to read the message. | ||
|
||
**Intercept:** In this case there would be no way to intercept the message without breaking the box or copying keys! | ||
|
||
## Extension | ||
|
||
Bob opens the box and see it is instructions to play a game. To start the game Alice and Bob will flip a coin to decide who goes first, however they will still need the messenger to communicate the outcome. Who should flip the coin? Who should choose heads or tails? How can they communicate in a way so that neither person can cheat? |
Original file line number | Diff line number | Diff line change |
---|---|---|
@@ -0,0 +1,50 @@ | ||
# Monkey Business | ||
|
||
## Introduction | ||
|
||
This is another problem where the solution seems impossible because there are too many things to consider (1000 monkeys!), but again becomes achievable once simplified and able to see patterns. To start the problem you should ensure students understand the rules, perhaps imitating with 4 students and the same number of coins or cards that can be flipped to face up or down. | ||
|
||
The first student flip all cards up (u): [u, u, u, u] | ||
There was a problem hiding this comment. Choose a reason for hiding this commentThe reason will be displayed to describe this comment to others. Learn more. This might be easier to format as a table than using spaces, but it is still fine like this |
||
|
||
The second student flip the evens down (d): [u, d, u, d] | ||
|
||
The third student would flip card 3: [u, d, d, d] | ||
|
||
The fourth student would flip card 4: [u, d, d, u] | ||
|
||
|
||
|
||
|
||
## Solution | ||
|
||
1.For the first part of the problem you only need to consider 10 monkeys (as the 11<sup>th</sup> monkey and later will not press any of the first 10 switches). So which monkeys will press switch number 10? Well, as 10 is divisible by 1, 2, 5 and 10 there are exactly 4 monkeys which will press the switch | ||
|
||
* Monkey 1 turns it on | ||
|
||
* Monkey 2 turns it off | ||
|
||
* Monkey 5 turns it back on | ||
|
||
* Monkey 10 turns it back off | ||
|
||
So switch 10 will be **off**. | ||
|
||
2.The next part is more challenging, but again relies of thinking about how many monkeys will press each switch. | ||
|
||
Switch 10 was off because every time one monkey turned it on another turned it off. We were able to split the number 10 into factor pairs (1x10, 2x5), which will always result in the light being turned off. | ||
|
||
Most numbers will be pressed by an even number of monkeys, e.g. 24 has factors (1x24, 2x12, 3x8, 4x6), so monkeys 1, 2, 3, 4, 6, 8, 12, 24 will press the switch, and as this is an even number the light will be off. | ||
|
||
Square numbers are the only ones which do not, e.g. 16 has factors (1x16, 2x8, **4x4**). Monkeys 1, 2, **4**, 8, 16 will press the switch, and as this is an odd number the light will stay on (monkey 4 won’t press it twice!). | ||
|
||
**So we just need to work out how many square numbers there are between 1 and 1000?** | ||
|
||
If we think about the larges square number less than 1000, **<span style="color:brown">30x30=900, 31x31=961,</span> <span style="color:red">32x32=1024</span>** | ||
There was a problem hiding this comment. Choose a reason for hiding this commentThe reason will be displayed to describe this comment to others. Learn more. Nice idea to pass styling direct! I'm not sure why, but this isn't working (an issue with the app code I think), so I'll investigate at a future point. For now to keep the emphasis for the final line I think we should just underine. I know markdown doesn't support this, but I think it will work with a
|
||
|
||
So there will be **31 switches left on**! (switch numbers 1, 4, 9, 16, 25, 36, ... , 900, 961) | ||
|
||
## Extension | ||
|
||
How many lights would stay on if only the even numbered monkeys decided to take their turn pressing the switches? | ||
|
||
|
Original file line number | Diff line number | Diff line change |
---|---|---|
@@ -0,0 +1,13 @@ | ||
# Picture Puzzles 1 | ||
|
||
## Introduction | ||
|
||
These problems can all be solved in different ways, but it is recommended you encourage students to use logic and reasoning skills instead of guessing numbers. Usually each line gives you a piece of information that you can use in the next, so you should think carefully about each piece of information before moving onto the next. The problems also get harder as you go, so encourage students to start with the top-left puzzle first. | ||
|
||
## Solution | ||
|
||
![](../../images/picture-puzzles-1-2.png) | ||
|
||
## Extension | ||
|
||
Ask students to try and make their own picture puzzles! |
There was a problem hiding this comment.
Choose a reason for hiding this comment
The reason will be displayed to describe this comment to others. Learn more.
n points