Progress report

This week I have been quite busy. Top of the list was to release the Elephant Memory app update to the App Store. We added another type of object to remember, as fans will soon notice.
Another activity has been the release of a new app I mentioned in the February 17 blog. That one should be on sale early next week, probably Monday 28th. Hence next week will witness two releases from Proctele AB. Not bad!
The third activity has been to develop an idea we got a couple of months ago. That app has largely been programmed, but it has to be finished. Possibly ready for sale in three weeks.

Soon to be updated: Elephant Super Memory Challenge: Recall This!

The application with the following names in the localized App Stores is soon to be updated:

• English:  Elephant Super Memory Challenge: Recall This!
• French: Challenge Elephant Super Memory: Rappel Ce!
• German: Elefanten Gedächtnis Herausforderung
• Swedish: Elefantminne: Memorera detta!
• Dutch: Olifant geheugen: Dit memoriseren!

The new version, v1.1, will contain a new type of objects to remember (in the first screen), namely the numbers 0 and 1. To facilitate the input of 0 and 1, a new type of keyboard was added, which only contains 0, 1, Clear, Ok keys. Minor bugs have been fixed too.

A more "living" blog

I thought I'd let you know that I've made some additions to the blog:

• The aquarium. Click on it to feed our fishes. Every click gives them one piece. Please don't hesitate to feed them, because these can be fed at any time without any damage.
• The Proctele video collection.
• More gadgets.

Another app coming soon

There's yet another Proctele app coming out in about two weeks. I'm not revealing anything about it now, except for one thing: It is written for a certain group of people, who are going to buy it with a smile. It's simply a must-have for them.
Now I'm going to write the sales pitch for App Store.

New Kids App called "I Practice Plus and Minus"

Proctele's new App has been released. It's called "I Practice Plus and Minus" and is written for the iPhone and iPod touch. It lets kids practice their addition and subtraction skills. My 8-year old son likes the game, so it must be pretty good.
You can adjust the difficulty by allowing larger terms and results. There's a settings screen for that. The default setting is for the term to be up to 9 and the result to be up to 20. 
The application has different names in the localized App Stores, as follows:

• English:  I Practice Plus and Minus
• French: Je pratique plus et moins
• German: Ich Üben Plus und Minus
• Swedish: Jag övar Plus och Minus
• Dutch: Ik Oefen Plus en Min

There's a built-in help in all the languages.

To make the game more versatile, it's possible to have terms and results as large as 99,998. Sums of that size can be a challenge even to good mental arithmeticians.
Here's a YouTube demo: http://www.youtube.com/watch?v=Qvg7qkvI0YQ

NumberWiz example with solution-reasoning, Tuesday

How do you add, subtract, multiply and divide 1, 7, 7, 10, 25, 100 to get 208 ?


The first thing I wanted to try was 108 + 100. However getting 108 out of 1, 7, 7, 10, 25 seems difficult. Other similar combinations don't look good either: 101 + 107 or 110 + 98 or 125 + 83. Using 100 does not look promising enough.


250 (10 x 25) seems a better starting point. We need to subtract 42, and now a solution comes to mind: 208 = 250 - (7 - 1) x 7. Solved!


But how about (7 + 1) x 25 ? We must get 8 out of 7, 10, 100. Impossible.


Try 7 x 7 x 100 / 25 = 196. We need another 12, but we can only make 11.


Try (7 x 7 + 1) x 100 / 25. We need to make 8 out of 7, 10. Impossible.


The NumberWiz game takes the 250 route as above. It seems the only solution.

NumberWiz example with solution-reasoning

How do you add, subtract, multiply and divide 3, 5, 7, 8, 25, 75 to get 127?


This time I'm showing how I reason to find a solution. 


First I thought that 127 is close enough to 125, so 5 x 25 = 125, need to add 2. Getting 2 out of 3, 7, 8, 75 was simple: 2 = 7 + 3 - 8. Hence 127 = 5 x 25 + 7 + 3 - 8.


Another thing I would try is adding 75 and 25 to get 100. Then it's a matter of getting 27 out of 3, 5, 7, 8. That's not so difficult. 27 = 5 x 7 - 8. Hence 127 = 75 + 25 + 5 x 7 - 8 = 100 + 35 - 8.


The NumberWiz game gave this solution: 127 = 5 x 3 x 8 + 7 = 15 x 8 + 7. Elegant.


What a great game this NumberWiz game! Visit http://proctele.se

Your memory: use it or lose it

Memory, like muscular strength, requires you to “use it or lose it.” The more you work out your brain, the better you’ll be able to process and remember information. Brain exercises that will improve memory include:

• Novelty and sensory stimulation. If you break your routine in a challenging way, you’re using brain pathways you weren’t using before. This can involve something as simple as brushing your teeth with your nondominant hand, which activates little-used connections on the nondominant side of your brain.
• “Neurobic” exercise is an aerobic exercise for your brain that forces you to use your faculties in unusual ways, like showering and getting dressed with your eyes closed. (See Keep Your Brain Alive Exercises in related links.)
• Learning new skills can be the most effective way to improve memory. Take a course in a subject you don’t know much about, learn a new game of strategy, learn a new language, or cook up some recipes in an unfamiliar cuisine. The key here is to choose something that interests you. The more interested and engaged your brain, the more likely you’ll be to continue learning and the greater the benefits you’ll experience.

So try the above and you might become the family's memory champion.

Source: http://helpguide.org/life/improving_memory.htm

Walking boosts memory power

Here's an excerpt from the BBC website: 
"Walking for 40 minutes a few times a week is enough to preserve memory and keep ageing brains on top form, research shows. Moderate exercise increased the size of the hippocampus, an area of the brain that makes memories, in 120 volunteers. The year-long trial, published in Proceedings of the National Academy of Sciences, showed performance on memory tests also improved." 
The article is on this link: http://www.bbc.co.uk/news/health-12325285

Having read the article, here's my suggestion. Play the Proctele game "Elephant Super Memory Challenge: Recall This!" to test your memory. Then take a relaxing walk. Then play the game again. According to the research report you might score better after the walk. Why not have some fun while finding out?

Divisibility by 8

Divisibility by 8 is determined by looking at the hundreds digit. If it's even, you only have to check the number formed by the last two digits for divisibility by 8. 


Example 468. The 4 is even, so we check 68. 68 is not divisible by 8. 
Example 672. The 6 is even, so we check 72. 72 is divisible by 8. Hence 672 is divisible by 8.


If the hundreds digit is odd, it works differently. Here we must look at the number formed by the last two digits + 4. If that number is divisible by 8, then the whole number is divisible by 8. Let's take an example with an odd hundreds digit. 


Example 568. The 5 is odd, so we look at 68+4 (=72). 72 is divisible by 8, hence the number 568 is divisible by 8. 
Example 972. The 9 is odd, so we look at 72+4 (= 76). 76 is not divisible by 8, hence 972 is not divisible by 8.

New app in the making

A new app is about to emerge from Proctele AB. It's educational and it's about numbers, as you might guess if you know our previous apps. I will not go into details now.

The first app from Proctele was NumberWiz. It's our brilliant interpretation of the Numbers-round in Countdown, the TV-program that has been a success in the UK since 1982(!). We intend to come with a variation of this app within a few weeks.

Our second app was Elephant Super Memory Challenge: Remember This! It's great for testing your short-term memory, or improving it. We are considering an update to this app soon.

We only make apps that are close to our hearts. Math has been a lifetime interest and memory training is a hobby of mine. Many years ago I used to try to remember number-plates of cars or the order of the tracks on my LP records, decimals of square roots and so on. Nowadays I use my memory for storing passwords. I have a lot of them, so to be safe I have stored them in a file too.
I hope you'll enjoy our coming app.


Don't forget to tell your friends if you like our apps. 

Answer to the difficult 969

The question was: How do you add, subtract, multiply and divide 3, 5, 7, 9, 75, 100 to get 969 ?

It's interesting to note that 969 = 323 x 3, so a first approach is to try to get to 323 using 5, 7, 9, 75, 100. That turns out to be possible: (75 - 9) x 5 - 7 = 323.

Answer: 969 = ((75 - 9) x 5 - 7) x 3 = (66 x 5 - 7) x 3 = (330 - 7) x 3 = 323 x 3.

A difficult NumberWiz (iPhone game) challenge.

Here's another NumberWiz challenge. This one is difficult. If you can solve it, you must be a number wiz.

How do you add, subtract, multiply and divide 3, 5, 7, 9, 75, 100 to get 969 ?

The above question is typical of NumberWiz, the game of arithmetics for iPhone/iPod touch. It is also adapted for the iPad, where it looks even better. Search for NumberWiz in the App Store. Or even better: search for Proctele in the App Store.

Divisibility by 7

Divisibility by 7 is surprisingly simple, although certainly not trivial. 
To decide the divisibility of a 3-digit number abc, do as follows: take ab and subtract c x 2. If the result is divisible by 7, then abc is divisible by 7. 
Example: 567. take 56 and subtract 7 x 2 and you get 56 - 14 = 42, and 42 is divisible by 7. Example: 871: 87 - 1 x 2 = 85. 85 is not divisible by 7.
What if your number is more than 3 digits? Then you use a rule to make it 3 digits. This is best illustrated by an example. 
Example: 1092. Split the number into 3-digit numbers, in this case 1 and 092. Then you subtract 092 - 1 = 91, which is divisible by 7.
Example: 2,890,034. You have three numbers this time: 2, 890, 034. You do 34 - 890 + 2 = -854. Remove the sign and continue with 854: 85 - 4 x 2 = 85 - 8 = 77, which is divisible by 7. Hence the number 2,890,034 is divisible by 7. Notice here that you do 34 - 890 + 2, not the other way round 34 + 890 - 2. So you start with a subtraction, then an addition, then a subtraction again and so on, if the number you begin with is sufficiently large.

Update to the homepage

I'd like to tell that I updated our homepage at http://proctele.se. There is now some more info about our apps. I added the iPhone screen shots, so the page is more colorful. On YouTube I added a shorter version of the demo video for the "Elephant Super Memory Challenge: Recall This!" app. It's here: http://www.youtube.com/watch?v=xNHjwsiO_Vc and is only 77 seconds long.


"Elephant Super Memory Challenge: Recall This!" and "NumberWiz" are both Great apps. I still enjoy them myself, even though I played them many, many, MANY times.

Divisibility by 4, 5 and 6

Here's the continuation of divisibility.

Divisibility by 4 can be found out by just looking at the two last digits. Say you have 36764, then you only have to find out if 64 is divisible by 4. If dividing twice by 2 is possible, then 64 is divisible by 4. 64 / 2 = 32. 32 is even and hence can be divided by 2. Therefore 64 is divisible by 4.

Another example: 36786. We need only look at 86. Divide by 2 and get 43. 43 can't be divided by 2, and we conclude that 86, and also 36786 is not divisible by 4.

Divisibility by 5 is as simple as divisibility by 2, only different. All numbers ending with 0 or 5 are divisible by 5.

Divisibility by 6 is tested for by checking divisibility by 2 and checking the result for divisibility by 3. Example 198: It's even and could therefore be divisible by 6. We divide 198 by 2 and get 99. We test if 99 is divisible by 3: 9 + 9 = 18. 18 is divisible by 3. So 99 is divisible by 3. Therefore 198 is divisible by 6. Again, 198 is even. We divided by 2 to get 99 and found 99 to be divisible by 3.