Multiplying Numbers and Decimals

Multiplying Numbers and Decimals.

Use a Calculator Efficiently.

Calculate with Decimals

Solve Real Life Problems

Add / Subtract 3 or 4 digits

Use BIDMAS (Or BODMAS)

Multiply or divide by 2, 3

or 4 digits

Multiply by a Single digitLevel 3

Grade G

Level 4

Grade F

Level 5

Grade E

Level 6/7

Grade D/C

On Your Mini Whiteboards…

•37 x 424

•9 x 1.6

•2.1 x 0.36

Learning Objectives (Today)

• To be able to use the grid method to multiply large numbers

• To use this knowledge in answering multiplication questions with decimals.

• To solve problems in Real Life contexts.

Multiplying Numbers…….

• If the number 3561 is made up of;3000 + 500 + 60 + 1

• And the number 4020 is made up of;4000 + 20

• What are the following numbers made up of?1. 25682. 20203. 50034. 3205. 424

2000 + 500 + 60 + 82000 + 205000 + 3300 + 20400 + 20 + 4

Quick Methods….• To calculate 20 x 30 I can use a quick method…a) Calculate the sum without the 0’s

2 x 3 = 6b) Add the 0’s back in to the calculation

There were two zero’s in my original calculation so my answer would be 6 + 00, or 600.Try these…1. 20 x 402. 20 x 503. 200 x 3004. 500 x 70005. 2000 x 90 x 200

8001,00060,0003,500,00036,000,000

Multiplying using the grid method.• 22 x 37…..

20 2

30

7

600+ 140+ 60+ 14

= 814

600 60

140 14

The Grid Method….• 461 x 22…..

400 60 1

20

2

8000 1200 20

800 120 2

8000+ 1200+ 20+ 800+ 120+ 2

= 10142

StandardHarder


•37 x 424

•9 x 1.6

•2.1 x 0.36

Plan for Number Scheme of Work…..







or 4 digits


Grade G

Level 4

Grade F

Level 5

Grade E

Level 6/7

Grade D/C





5

2584

Double decimal trouble!

=43 x 67..

REMEMBER

Old answer was…2

Count the decimal places!

48

2

2

.

25.84

153

56 x 0

Decimal dilemma!

Where would the decimal point go in these answers?

7 x 36 =1692.4

45 =2520..

4.76 23 x. =46102

0 03 x. 0 51. =

153

56 x 0

Decimal dilemma!

Where would the decimal point go in these answers?

7 x 36 =1692..4

45 =25 20..

4.76 23 x. =46102.

0 03 x. 0 51. = 0.00.0153

Re-Cap…..

• Do the calculation as normal without the decimal points.

• Count how many times the numbers (or decimal point if it helps) have moved.

• Move the same number in your answer.

Words! Words!

26 people each buy a ticket to see a show.Each ticket cost £7.60. How much did theypay altogether?

A box of sweets costs £5.45. Ben buys32 boxes for his shop. How much did he pay?

Catherine wants to book a hotel room forher holiday. She wants to book for 17 nights.The room costs £37.86 per night.

1 2

3 4

Work out the answer to each question.You MUST show your working out!

£197.60 £174.40

£643.62

£55.83

a) How much will the room cost?

b) She counts her money and finds she has £587.79. How much extra does she need?

John wants to book a meal for him and 38other friends to celebrate his 30th birthday.Each meal costs £17.79. John has saved £700.

£693.81

Yes by £6.19

a) How much will the meal cost John?

b) Has John saved enough money, and if so, by how much?


•37 x 424

•9 x 1.6

•2.1 x 0.36

Plan for Number Scheme of Work…..







or 4 digits


Grade G

Level 4

Grade F

Level 5

Grade E

Level 6/7

Grade D/C





• Reflection on Today’s lesson….

• Give yourself a colour for Work ethic and a number for Understanding

Today I have

enjoyed…

Documents

Multiplying Numbers and Decimals