Measuring Weight: Calculating Differences

In this activity, we will be learning to compare weights in grams. 

 

Measuring the weight of something is a way of working out how light or heavy it is.

We often use weighing scales for this, similar to those in the pictures below.

 

We will be comparing weights in grams and we may need to do some adding up or subtracting before we can answer the question.

You could use mental methods, or written methods to do this and it might help to jot down your calculations on paper while you are working.

 

Let's go ahead and try an example together, as an introduction to this activity.

 

Example

 

Which is heavier, the rice or the biscuits?

How much heavier?

 

Rice	Biscuits

 

Answers

 

First, let's find out which weighs most by using some mental calculations.

The rice weighs 450 grams

400 + 50 = 450

The biscuits weigh 350 grams.

300 + 50 = 350

So, the rice is heavier as it weighs more.

 

Now, we can use subtraction to work out how much heavier the rice is, compared to the biscuits. 

Find the difference between the two weights: 450 g - 350 g = 100 g 

The rice is heavier by 100 grams.