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Key constructs: Number x Value, External Change, Gaps & Differences

KEY constructs in Conquer Problem Sums series of books are introduced/developed in Primary 3 (P3), and further developed across Primary 4 (P4), and applied extensively in Primary 5 (P5) especially for the fundamentally important topics of Fraction, Ratio and Percentage. The problem solving emphasis in the books is always on gaining a conceptual understanding first following by the procedural or method application step to arrive at the solution, as explained in the Introduction to ThinkingMath.
In this article, we focus on three key constructs: Number x Value, External Change, and Gaps & Differences.

FOR the convenience of the parent or educator using Conquer Problem Sums (P3, P4, P5, P6), we have cross-referenced key constructs (applied in the books) to sample associated units of the appropriate topics where they are applied.

Number of Units x Value of Units

The Number x Value key construct is used in all the four books (P3 - P6).

You can apply this key construct when you know the number of items (usually expressed in fractions, ratios, or whole numbers) as well as the value of each item (individual amount).

For further practice and more examples, click on the following:
More samples from Conquer Problem Sums series

External Change

The External Change key construct is used in the P3, P5 and P6 books.

This key construct is so named because in such a problem the individuals, groups or objects all experience change. The model drawing takes place when all have an equal amount.

For further practice and more examples, click on the following:
More samples from Conquer Problem Sums series


Gaps & Difference

This key construct is introduced in the P3 book. Look out for statements that use the term ‘short of'. This means some amount is required to add to the original amount to compute what is actually needed.

For further practice and more examples, click on the following:
More samples from Conquer Problem Sums series


Click below for other articles in our series on key constructs:

Introduction to ThinkingMath / Key constructs in Conquer Problem Sums
More Than/Less Than (Comparison, Division)
More Than/Less Than (Types 1 - 3)
Equal Stage
Repeated Identity
Part-Whole Relationship
Equal Fractions, Internal Transfer, Guess & Check

 

 

Comments (10)add comment
limzhiyan
limzhiyan: Key constructs: Number x Value, External Change, Gaps & Differences
so less p4 one
1

April 23
Chris Rogers
Chris Rogers: Key constructs: Number x Value, External Change, Gaps & Differences
Hi there. I do not quite understand your comment. Are you asking a question regarding Number x Value?
2

April 23
harini
harini: Key constructs: Number x Value, External Change, Gaps & Differences
Ya! there are so less p4s! But the informations are helpful! smilies/cry.gif smilies/cheesy.gif
3

July 10
Chris Rogers
Chris Rogers: Key constructs: Number x Value, External Change, Gaps & Differences
There are so less p4s ??? Sorry this is not very good English. Are you trying to suggest that the questions are not for P4? If so,you are correct most of the questions in the forum are asked by P5 and P6 students. Perhaps that is because the questions are more difficult ??
4

July 11
boonhao
boonhao: Key constructs: Number x Value, External Change, Gaps & Differences
p6 damm hardsmilies/cry.gif
5

February 12
boonhao
boonhao: ...
espically simultaneous
6

February 12
Jen Chan
Jen Chan: Key constructs: Number x Value, External Change, Gaps & Differences
P6 SUPER HARD
7

April 30
shawn guek
shawn guek: Key constructs: Number x Value, External Change, Gaps & Differences
P6 PSLE is going to be hard this year!!!smilies/angry.gif
8

May 22
Hana
Hana: Key constructs: Number x Value, External Change, Gaps & Differences
omg sa1 was so difficult. but i atleast i managed to get A but i must get A star for psle..........
9

May 23
Gabriel Ong
Gabriel Ong: Key constructs: Number x Value, External Change, Gaps & Differences
o.O External Changed not in P4 eh?
10

July 24

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