In this activity, we are going to be adding and subtracting some measures.

We'll need to convert some measures as some objects may be in a different unit of measure.

We'll need to know these facts:

10 mm = 1 cm

100 cm = 1 m

1,000 m = 1 km

1,000 g = 1 kg

1,000 ml = 1 l

Let's get started:

A B

Jug A has 2 litres of orange.

Jug B has 400 ml of orange.

How much orange is there altogether?

__Answer:__

In this question, we need to convert the units of measure so that they are the same.

We know that 1 l = 1,000 ml so 2 l = 2,000 ml

So jug A holds 2,000 ml

Jug A = 2,000 ml

Jug B = 400 ml

2,000 + 400 = 2,400 ml

There is 2,400 ml of orange juice.

We could also convert this back to litres by dividing by 1,000.

2,400 ÷ 1,000 = 2.4 litres.

Let's have a look at another question:

The chair is 98 cm tall.

How tall would two chairs be?

In this question, we simply need to add 98 cm and 98 cm = 196 cm

Two chairs would measure 196 cm.

Let's have a look at one more question:

The shopping bag weighs 1,100 g

4 apples weighing a total of 200 g are taken out.

What does the bag weigh now?

To answer this, we need to do a subtraction (subtract the weight of the apples)

1,100 - 200 = 900

The bag now weighs 900 g

Now it's your turn to have a go at some questions!