Stabroek News Sunday

MATHEMATIC­S

- Hello boys and girls, Have a blessed week. Goodbye.

Last Week’s Answers

I hope your week at school was enjoyable. Last week we looked at measuremen­t, where we converted units in mass from one unit to another. This week, however, our main focus will be based on the measuremen­ts of capacity.

Work cautiously, please.

Measuremen­t

To answer a question like ‘How much water is in the bottle?’ we need measuremen­ts of capacity. Capacity is usually used for fluids.

Now, what is ‘Capacity’ in Math?

Have you ever noticed that there is only a certain amount of water that can be filled in a pan or a bottle? The maximum amount for all sodas and chocolate syrups is printed on the container. Capacity is defined in mathematic­s as the maximum amount a container can hold when full.

In the metric system, the standard unit for measuring capacity is the LITRE, and the symbol used is ‘L’

In mathematic­s, there are two basic/common units used for measuring liquid. They are the Litres and the Millilitre­s.

Ok boys and girls, before we dive deeper into today’s lesson, as our first activity, let us test our reasoning skills and answer the following questions:

Activity 1

1. How many ½ litres are there in 1 litre? 2. How many half litres are there in 2 litres? 3. How many ½ litres are there in 5 ½ litres? 4. How many litres are there in 4 ½ litres?

Fill in the missing quantities below.

5. 1L = ¼ L + __L + __L + __L

Great! I am confident that you have mastered that activity! You can ask a parent or sibling to check your work.

Let us move on. We’ll now examine how we can convert from one capacity unit to another.

Here are the formulae we apply, when converting

1/2 litre = 500 millilitre­s 1/4 litre = 250 millilitre­s

Point to note:

When changing a large unit to a smaller unit, we

Keeping this in mind, let us examine how we can convert litres to millilitre­s.

Conversion of Litres to Millilitre­s Example 1:

Change 2 litres to millilitre­s.

Since 1000ml= 1 litre, multiply 2 by 1000 2 x 1000 = 2000ml

Example 2

from one unit to another:

1000 millilitre­s = 1 litre

Change 7.2 litres to ml.

Since you are multiplyin­g a decimal by 1000, shift the point three places to the right.

7200 x 1000 = 7200ml

It’s that simple! Let’s practice working a few.

Activity 2

Convert the following litres to milllitres. a. 3L b. 4 L c.9L e. 6.7 L f. 6.45 L g. 4.38 L

MULTIPLY.

d. 3.5 L h. 2.365 L

Good job, boys and girls!

So, what do you think we should do if we want to convert a small unit to a larger unit? That’s right!

When changing from a small unit to a larger unit, we DIVIDE.

Hence, let us examine how we can convert from milli litres to litres.

Converting Millilitre­s to Litres Example 1

Change 4000 millilitre­s to litres.

Since 1000 ml = 1 litre, divide 4000 by 1000 4000 ÷ 1000= 4L

Example 2

Change 7560 ml to litres.

Since you are dividing by 1000, shift the point three places to the left.

7560 ÷ 1000 = 7.560 L

Now, let us apply the concept we have learned, by working the following exer cise:

Activity 3

Convert the following to Litres: a. 2000 ml b. 12000 ml d. 80 ml e. 256 ml

Great job, boys and girls!

Now that you have gained the knowledge on how to convert from one capacity unit to another, let me test your knowledge using the following quiz.

Complete the quiz below as your final activity:

Activity 4-Quiz

c. 5960 ml f. 450 ml

Convert the following as indicated.

1. Change 2 L to ml.

2. Convert 6.35 L to ml.

3. Change 300 ml to litres.

4. Convert 8 ½ litres to ml.

5. Convert 9 ¼ litres to ml.

6. A water tank contained 2450 L of water. A further 760 L were added to com

pletely fill the tank. How much water does the tank contain?

7. A kerosene tank holds 450 L of kerosene. If 95 L were sold on Saturday, how

much kerosene remained in the tank?

8. A taxi driver used 45 L of petrol in each of 5 working days for the week. How

much petrol did his car used altogether?

9. Given below are 6 bottles with different capacities. Use 2 or 3 different bottle

combinatio­ns to form the given quantities.

That’s all for today boys and girls. Thank you for being receptive to the knowledge you were exposed to. Check back next week for the answers to this week’s problems. In our next lesson, we’ll be examining the concept of the perimeter of shapes.

 ?? ??
 ?? ?? (i) 1500 ml (ii) 750 ml (iii) 1100 ml
(i) 1500 ml (ii) 750 ml (iii) 1100 ml
 ?? By Stayon Abrams ??
By Stayon Abrams

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