MATHEMATICSConverting between different units

Lesson Objectives

•The aim of this powerpoint is to help you…

• Convert between different types of metric units for

• Length

• Mass

• Capacity

Metric Units

• LENGTH

millimetre (mm)

[centimetre (cm) 1cm = 10mm]

metre (m) 1m = 1000mm

kilometre (km) 1km = 1000m

Metric Units

•MASS (WEIGHT)

milligram (mg)

gram (g) 1g = 1000mg

kilogram (kg) 1kg = 1000g

tonne (T) 1T = 1000kg

Metric Units

• CAPACITY

millilitre (ml)

[centilitre (cl) 1cl = 10ml]

litre (l) 1l = 1000ml

Metric Unit Conversions

• For length, capacity and mass if ‘centi’ is not involved, you need 1000 units to make 1 of the next sized units

• To convert large type units to smaller ones, multiply by lots of 1000

• To convert smaller type units to larger ones, divide by lots of 1000

Multiplying/Dividing by 1000

• 1000 is 1 followed by 3 zeros

• Multiplying by 1000 results in moving the decimal point 3 places to the right to make the number bigger

• Dividing by 1000 results in moving the decimal point 3 places to the left to make the number smaller

LOGIC

• Check your answers by asking yourself whether they make sense.

• If they do NOT make sense you have probably multiplied when you should have divided or vice versa!

• Remember if you have big units and you change them to smaller ones there will be a lot more of the smaller ones!

Example 1

• Convert 7m to millimetres

Metres are bigger than millimetres

Converting bigger to smaller multiply by…

‘Centi’ is not involved so 1000

7m × 1000 = 7000mm

Example 2

• Convert 85ml to centilitres

Millilitres are smaller than centilitres

Converting smaller to bigger divide by…

‘Centi’ is involved and the link between ‘centi’ and ‘milli’ is 10

85ml ÷ 10 = 8.5cl

Example 3

• Convert 0.64km to millimetres

Kilometres are bigger than millimetres

Converting bigger to smaller multiply by…

‘centi’ is not involved so 1000 (twice!!!)

0.64km × 1000 = 640m × 1000 = 640 000mm

What next?• Print out the notes called Meas2. Read through them and

make sure you answer any questions on page 6.

• Work through the MyMaths lesson and its online homework called Metric Conversion found at:

• http://app.mymaths.co.uk/279-resource/metric-conversion• http://app.mymaths.co.uk/279-homework/metric-conversion

• Now move on to the Meas2b powerpoint