More on Measurement

Not drawn to scale

Notice the parts on the weighing balance in my previous post? Now, when we are given any scale, we can see it being applicable to any standard units (e.g. m, cm, kg, g) as long as we understand how to find the parts within the scale.

Using the scales above to measure an eraser, the children can give me a more precise answer when it comes to its length. We started with 'about 4 cm' using the scale right on top. Then we move down to the one below and measured 'between 3.5 cm and 4 cm' and finally we had '3.8 cm' as the answer. Therefore, we can conclude that the scale at the bottom can give us the most accurate reading here.


Do note that the topic decimal is not in P2 syllabus.


However, the children will need to know to how to read the scale on a weighing balance where the indicator does not point exactly to the numbers on the scale. Each shorter line stands for a value.

Note the red dots marked on the weighing scale. We take interest in the shorter lines between 30 kg and 40 kg. Now, when the indicator does not stop at the number, the children have to find out the value of each part.

Think 'number patterns' when we do this. A guess & check can be done to find out the answer.


An example of thinking aloud:

First, let's see where the indicator points to. (between 30 kg and 40 kg)


Then, let's do 'counting on' based on the guess and check method.


30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40






Let's take a look at another example:

The heaviest item that this weighing scale can measure is 100 g. When the children are given questions like this where the indicator is not pointed to a given number, they have to figure out themselves.


Let's try the 'counting on' using the guess and check method.
I pay attention to the shorter lines. (There are 9.)
So, I can count on from 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30.
Therefore, when I reached the 30 g mark, I am sure that each shorter line represented 1 g.

Math workbook Part 2 pg 82

There are 2 things to note in this pupil's work. First, I can conclude that this child is ready to handle some concepts of decimals. I can use language like '0.5 kg' in my explanation. I will be able to ask this child to solve this addition number sentence 6.5 + 0.5 = ? Second, I am sure this child did not check the numbers given after 6. He/ She wrote 6.5 kg because it happens to be a halfway mark.


It will be confusing to the children if we introduce them to a new concept (decimals) just to explain another new concept. Therefore, build on their prior knowledge of 'counting on'.The shorter lines have numbers which are missing just like in a number pattern. As usual, we do a guess and check.


6, __, __, __, 8


6, 7, __, __, 8 (wrong)


6, __, 7, __, 8 (correct)


6, 6.5, 7, 7.5, 8 (correct but the topic decimals is not in P2 syllabus)






Topics involving measurements include 'length', 'mass' and 'volume'.



That's all!