P2 Math - General Discussion

[metz]

It’s considered as bars of tens in the Tens columns. Therefore, in the above pic, it simply implies 2 bars of tens = 2 tens = 20.


The use of bars of tens in the Tens columns seems to be a standard practice. And that goes for hundreds too. Usually, a 10x10 block will be used to represent 100. So, 2 10X10 blocks = 200.

So far, I have yet to come across questions that put single blocks in the Tens/Hundreds columns.

[buds]

I agree with chamonix on this. The application of operations

using such materials be it cubes or beads simply implies what
it really is... visually.

Montessorian children are guided on systematic steps; on how
they should work with the Golden Beads during the early stages
of learning math operations in the Montessori Math curriculum.

The calculation of units are only up to 9 units or 9 ones. Each time
the units total up to ten units, children are to exchange with the
bank (teacher), for a ten bar..

They are also taught to count in tens....
> 1 ten bar is also 10.
> 2 ten bars is also 20.
> 3 ten bars is also 30.... and so on.

They get to work with the bars on their own,
with the teacher and also in groups as revision
games. Children take turns to arrange the number
of ten bars and the rest in the group must tell the
answer. Children also get to match number cards
corresponding to the beads shown on their work
mats.

In the case of this question... should they work with
number cards, the cards they would take would be
20 and 10. The cards cannot be read as 20 and 10.

In this case, where the eventual value is asked of the diagram, i
find there is no ambiguity of any kind. It is kinda straightforward.

a. 210 does not justify the 2 tens in actual fact. Unless if it is phrased
as 2 tens or 2 10's and provided the answer (30) isn't one of the MCQ
answers.

b. 210 cannot be the eventual answer as the diagram cannot be read
as 2 ten 1 ten or twenty and ten.

c. 210 cannot be the eventual answer since as both my DDs said..
:slapshead: that number is read as two hundred and ten, not 2 ten.

Just sharing.

[corneyAmber]

Thanks chamonix n buds, I can see the convention now, in fact all of you explain very well so I can get the idea even before checking textbook.


Using the same approach or convention,here is another question.

How many tens are there in 751?

[sleepy]

ksi:

Which would you choose?
1. 20
2. 29
3. 30
4. 210

Is this question considered tricky or ambiguous??? :?

My dd's answer is 3
2 tens and 10 ones

ksi:

How many tens are there in 751?

My dd's answer is 75

[metz]

ksi:

Using the same approach or convention,here is another question.

How many tens are there in 751?

It all depends on the context of the question.

If the question is a standalone question, 75 tens should be the acceptable answer.

But if the question is phrased as such - ___ hundreds, ___ tens, ___ units

then I believe the appropriate answer should be 5 tens.

[sunflower]

chamonix:

ksi:

Using the same approach or convention,here is another question.

How many tens are there in 751?

It all depends on the context of the question.

If the question is a standalone question, 75 tens should be the acceptable answer.

But if the question is phrased as such - ___ hundreds, ___ tens, ___ units

then I believe the appropriate answer should be 5 tens.

Agree! :celebrate:

[UmmuMuadz]

Hi,


I was going through DS1’s Maths Textbook yesterday.. He’s in Primary 1.

Under the topic addition / subtraction within 20, the method is follows:

12 + 3 = ___

First, break the 12 into 10 + 2

Second, take 2 + 3 = 5

Lastly, the to get the answer, you take 10 + 5 = 15

This is the method he was taught in school. This is the first time I come across such method. :shock:

When asked whether he understands this method, he said no. Instead, he is using the old school method of putting 12 (in the head) and calculate using the 3 fingers to add on.

I would like to ask if the textbook method better in terms of making the child understand the concept as compared to the old school method?? :?

Thx

[corneyAmber]

This new method uses the strength of number bond for 10s to help the children calculate faster.


Using fingers for calculation has its limitations so it is not encouraged as numbers get bigger.

Abacus method also uses number bonds of 5 and 10 to calculate big numbers.

[buds]

UmmuMuadz:

Hi, I was going through DS1’s Maths Textbook yesterday.. He’s in Primary 1.

Hi there UmmuMuadz... same here, my DD2 is in P1 as well.

UmmuMuadz:

Under the topic addition / subtraction within 20, the method is follows:

12 + 3 = ___

First, break the 12 into 10 + 2

Second, take 2 + 3 = 5

Lastly, the to get the answer, you take 10 + 5 = 15

This is the method he was taught in school. This is the first time I come across such method. :shock:

If you have noticed... the FAN-Math books that you got from me also
encourages the method used above. It so calls encourages children
to find it easier to calculate without the use of fingers, stick or circle
drawings, or even the number line... it moves towards the method of
speed maths which is more of a mental calculation.

During the early stages of Primary education, it is more on these number
bonds' skills, which if nurtured; can be automatic for them and assist them
to solve math workings much faster.

UmmuMuadz:

When asked whether he understands this method, he said no. Instead, he is using the old school method of putting 12 (in the head) and calculate using the 3 fingers to add on.

While there is nothing wrong in using the old school safe method of
counting, it is still nevertheless essential to learn it... cos i dunno lah
yah... it comes out in the children's assessment/class test and exams
(at least for both of mine).

UmmuMuadz:

I would like to ask if the textbook method better in terms of making the child understand the concept as compared to the old school method?? :?

If the child eventually grasps the concepts, understands how it simplifies
their counting process and in the end, able to apply this method in his or
her assignments, then the answer would be a BIG yes to it being a better
method as compared to the traditional ones..

PS : If you've noticed, the textbook method introduces the ability to *so-
call calculate faster when one number is rounded off to ten. As the
numbers get bigger later on... i assure you they will (become bigger!)...
children will have to round off one number in math questions like the one
above, to the nearest ten.. ie. 22+5 is broken up to 20 and 2+3..

*Why so call? Cos while it challenges my DD2 to work with even bigger
numbers, my DD1 finds it a hassle and like your son, she used to say
dunno... dun understand... and also dowan to understand.. :politebleah:

:faint:

So, UmmuMuadz... hope this helps.

[UmmuMuadz]

Hi ksi and buds,


Thanks for the clarification

I guess when I saw it for the first time last night, I felt that its quite confusing, well at least to the \"old skool\" brain of mine

It took me longer to solve the problem using the textbook method but my son could do it quite quickly. :lol:

In fact, he was also showing me how to solve 22+5 using the textbook method. I bet he can also solve 30, 40 using the same method. Come to think of it, he did understand what the teacher taught him. Thats a relief.

Thanks again for the clarification. :celebrate: