Multiplying Decimals

0.5

2.8$4.55

0.75

$7.45

6.5$8.65

When would you need to multiply a decimal?

Revising Decimals

30 out of 100 = 30/100 = 0.3

58 out of 100 = 58/100 = 0.58

4 out of 100 = 4/100 = 0.04

Multiplying Decimals

0.6 x 0.4 =Shade 60/100 in one colour horizontallyShade 40/10 verticallyWhat is the value of the area that is double shaded?

0.24 - therefore0.6 x 0.4 = 0.24

or

0.6X 0.4

.24

Multiply ignoring the decimal points6 x 4 is 24

Now put in the decimalsIn this equation, there are two decimal places, therefore you need to keep two decimal places

24 becomes 0.24

Let’s Practise!

0.8 x 0.2

0.8X 0.2

0.24 x 0.3

0.24X 0.3

4 x $ 2.25

$2.25X 4

I need 5 kg of potatoes for my recipe. Potatoes cost $1.25 kg. How much will the potatoes cost me?

Thomas is building a square frame.Each length needs to be 1.2 metres.Four lengths are needed for the frame.What is the total length of wood needed to build the frame?

Using a 10 x 10 grid, solve the following:

0.6 x 0.3 = 0.9 x 0.4 =0.5 x 0.2 =

Now solve these:

5 x 0.65 = 0.99 x 0.4 =6.5 x $1.65 =

Play Doggone Decimals!You'll need: A partner1 deck of 0-9 cards (4 cards of each number)1 calculator 4 bingo chips ( 2 each)4 decimal cards marked: 1, 10, .1, .01

To Play:Each player is dealt 4 cards and given 2 bingo chips. The 4 index cards are shuffled and the top one turned over. This is the "target number". Players must use the 4 cards they were dealt and bingo chips (for decimals) to create numbers that when multiplied will come as close as possible to the target number. (The decimal may be placed anywhere in the number. . . ie...48. , 4.8, .48. )The winner takes all 8 cards.

Play ‘Buzzing for products’

with a partner!

Plan a dinner party for 20 people!Using grocery store catalogues, plan:*Drinks*Dinner*Snacks*Dessert

• You will need to work out how many bottles of soft drink, how many kilos of meat and vegetables, packs of snacks, tubs of ice cream etc and record.• Create a shopping list including the quantities of each product required.• Using your knowledge of how to multiply decimals, calculate how much it will cost for each item.• Now add up the total cost of all items for your dinner party.

Item Cost Quantity TotalCola - 1litre $1.25 3 bottles $1.25 x 3 = $3.75

Lemonade – 1 litre $1.20 2 bottles $1.2 x 3 = $3.60

steak $6.55 kg 3kg $6.55 x 3 = $19.65