Perbedaan Teknologi vs Engineering dalam STEAM

Munculnya istilah STEAM dalam konteks pendidikan membuat sebagian orang bertanya, "apa perbedaan Teknologi dan Engineering?".

STEAM singkatan dari Science, Technology, Engineering, Art dan Mathematics dipercaya sebagai satu kesatuan subject yang harus diajarkan ke anak-anak untuk menjawab tantangan masa depan. Dalam konsep STEAM, kelima subject tersebut menjadi satu kesatuan. Hal ini sejalan dengan konsep thematic dan project based learning yang sedang dikembangkan dalam kurikulum nasional.

What is square root of 4

It seems that after learning quadratic equation, some students confused about square root. They thought $\sqrt 4$ can be -2 or 2.

No! $\sqrt 4$ is $2$

But (you may say),  $(-2)^2$ is also 4. Doesn't it mean -2 is also $\sqrt 4$

Nope! By convention squared root of a positive number is always a positive number.

But, if you are asked to find x that fit in this equation $x^2 = 4$ the answer $x = \pm \sqrt 4$.

See here, the value of x that fit to that equation is $x = -\sqrt 4$ or $x= +\sqrt 4$ and $\sqrt 4$ is 2.

Solution to Singapore maths question that stumped the world

Singapore maths question stumped the world

The following question has stumped the world. It was circulated that this is a fifth grader exams question, but later verified that this is actually 14 year old questions


Albert and Bernard just became friends with Cheryl, and they want to know when her birthday is. Cheryl gives them a list of 10 possible dates.

May 15 May 16 May 19

June 17 June 18

July 14 July 16

August 14 August 15 August 17

What is 1 divided by 0?

$\frac 10 \neq \infty$

Some say 1 divided by 0 is infinity. They argue that when a number is divided by smaller number the result is bigger number. And if we divide a number with a very very very small number it will give a very very very big number. According to them zero is a very very very small number therefore 1 divided by 0 will give infinity (a very very very big number). Is that true? NO!

Do we have to pay to create iOS apps?

I received this question in several occassion. I'd better write the answer here for others with similar question.

Short answer : YES, if you want to become serious iOS developer. How much? $99 annually.

Long answer:

Freezer that can reach -300C

If, and only if, in the future our technology in making freezer is very-very advanced, can we make a freezer that is very cold and reach -300 Celcius?

What for? Anything, to freeze living human body like in Terminator moview. Who knows?

Okay, back to the question. Can we or can't we?

The answer is : NO, we can't! The lowest we can get is -273 Celcius or 0 Kelvin which is why the call it zero absolute.

Here is the explanation

Limit and infinity

limit x mendekati 8

Just got this 'story' from twitland

After explaining concept of limit and give example as shown above, the teacher try to test students see if they understood. And the following is the student's answer


hmmm... something wrong?

Why Should We Standardize Process Diagram?

non standard business process

One of the reason BPMN exist is to standardize how we draw business process diagram. Without standard, one can draw business procees in many ways, often not understood by others.

To illustrate it, below are several diagrams for the same process I found on google.

Strange Division

8 divided by 2

I found an interesting "concept" of division on a Facebook timeline. I draw an image (above) to ilustrate it and save it here for future reference.


What is 8 divided 2?


It depends on how you divide it. If divided horizontally it becomes 0 each. But if it is divided vertically, it becomes 3.

In BPMN Gateway is NOT Decision!

gateway vs decision

In a BPMN diagram, a diamond shaped element as shown on the diagram above is called gateway. In a conventional flowchart, a diamond represent a decision. What is the difference between gateway and decision?

A decision involve an activity to determine the condition, whereas in BPMN, gateway is alternative sequence flows