Hi! Refer to the explanation below for details. (a) 24 x 12 = 288 288 square cm (b) 1/2 x base x height 1/2 x 6 cm x 12 cm = 36 square cm Area of shaded parts 288 - 36 = 252 Area is 252 square cm. :)

Hi! That would be 58 - 20. Angles opposite each other in a parallelogram are equal. Meaning, angle BCD equals to angle BED.

Hi! Let 1 unit represent the number of children. So, you have 5 units representing the number of adults. So, we have 6 units to represent 360 people in the pool. So, 1 unit represents 60 children and 5 units, 300 adults. You can now solve the rest of the problem. :)

You should write train-> 1/8=5/40 instead of the second one. Writing mathematics should be meaningful and elegant though you can understand your work fully. Remember that mathematics is universal.

I understand what u mean...but what is the directive behind it... Will the student be penalised..or marks will be deducted for the working?

That point is under the authority of the teacher. Usually the teacher had arranged a full assessment framework or rubric. A good teacher never lets his student does the similar thing.

A train cannot be equal to 1/8.

(Train) (Car) (Bus) (Total Distance) Simplifying explanations of math statements. I agree with the 19 units = 38 km statement because what will you want to use if you don't have the equal sign? Simply drawing an arrow to represent an equal sign is simply cosmetic in nature when we are still using the function of the equal sign to carry out an operation.

the one-directional arrow is actually misleading, because the relationship is symmetric i.e. if a = b, then b = a. Personally, I can accept the statement 19 units = 38 km, provided your "unit" is allowed to include km. Usually in maths, we focus on the numbers. I usually use a bidirectional arrow e.g. 19 units <---> 38 km. This notation thing may sound like nit-picking, but these habits carry over to secondary school. and then the students have to unlearn their old notation and relearn the algebraic notations which always use "=". Therefore parents, teachers and tutors should get this right themselves.

Izam Marwasi I have removed my earlier comment to your question, and that's because someone issued a reply with a ' say who ', and I will not want to engage in a war of words. The lengthy explanation provided by some within the education fraternity is good in my opinion, minus the intention to tell tutors , parents and teachers to get the concepts clear. At the end of the day, we are all here to help.

Hi..

Hi

Hi...thanks everyone for the detailed explanation.. Very educational... I pick up this qn from one of the Google apps and the solution given is below.. Once again ..thank you..

I like to use equal signs when two numbers are equal to each other i.e. 1/8 = 5/40 When i'm assigning a number to a categorical thing, i will use a 1 way arrow, since that word implies that number, but that number does not imply that word i.e. Train --> 1/8 When in the case of the question you have two numerical things equivalent to each other in the question but not necessarily outside the context of the question i prefer to use a two sided arrow for the first line, since we're basically making a statement i.e. 19 units <--> 38km Then any calculation after that i would use an equal sign, since we've already defined what implies what i.e. Therefore 1 unit = 2km Your last line would then be written: Distance between two places --> 40 units 40 units = 80km Therefore distance between two places --> 80km This is just how i was taught at university and the way i see it is the implications of the signs that make a difference, it's also easier to see where your assumptions are, therefore pick up any mistakes you may have made based on your assumptions

in university, the implication symbols have double lines e.g. ==> , <== and <===>. the main problem IMHO is that in Singapore maths, we have evolved a sub-culture of using a single-line single directional arrows ---> which I am not sure what they really mean, or even make sense. if everybody is taught to follow and do follow one convention e.g. Matthew Thomas, then its fine. now different people have different interpretations. it looks like after attending some workshops, some teachers stopped writing silly things like "train = 1/8" but it seems that they half-understood the intent of those workshops, which is about CLEAR COMMUNICATION. some folks began to use the single-line single directional arrow and it has became part of the Singapore maths sub-culture. [ another feature of the Singapore maths sub-culture is the use of the letters "u" and "p", for "units" and "parts" which mean the same, but are used for denoting different types of ratio units. ] i get very suspicious of using the single line single direction arrow because some relations (e.g. equal, equivalent) are symmetric. If we just use plain English, e.g. "the distance between two places is 80km" "80km is the distance between two places" we see that both statements are fine and that you can swap the things on the left and on the right of the word "is" and the statement is still correct. But using the single-directional arrow ... "distance between two places --> 80km" now what? what does this mean? can you swap the 80km to the front? why? or why not? the problem gets compounded when students go on to secondary school. Many are reluctant to kick the habit of using the single-directional arrow at places where they should be using the = sign.

When you use the '=' sign, it means 'is the same value as'. So whatever is on the left hand side 'is the same value as' what is on the right hand side. When you say '1/8=5/40', this is mathematically correct. Now read 'Train=1/8', how is this expression correct?

because a train is a physical thing whereas 1/8 is a number. neither the twain (train?) shall meet.

do we want to "help" based on personal opinion and pride, or based on what is right? if we do not show a good example to our children, how can the children learn the right thing?

I do believe that the author of the reply to my post has positive intentions, but I do feel the respect for fellow educators is paramount too. To issue a response such as ' says who ' to my post brings me to think of the intention of the author. Is the author trying to show his competency, or trying to discredit another educator? A more positive way to clarify would be thru pm, to point out the mistake, if there is any in the first place. I am an educator for students, and not for fellow educators. As such, this is solely my view.

It's just to clarify the truth. No personal attack intended. A humble person will not feel easily offended.

Indeed. I will leave it to parents here to make a judgement call on some of the ethical practices of educators as well as some of the statements made.