kungfu math p4 slide14 (multiplication decimals)pdf

• multiplication of decimals (up to 2 decimal places) by a 1-digit whole number

What will we learn today?

Decimals Multiplication

In the previous lectures, we have learnt about

addition and subtraction in decimals.

Let’s recap!

Applying what we have learnt

Try this out!

Mr Li used 2.5kg of rice on Monday and 1.75 kg on Tuesday. He used a total of 9 kg Monday and Wednesday. How much rice did he use on

Wednesday?

Solution

Mr Li used 2.5kg of rice on Monday and 1.75 kg more on Tuesday. He used a total of 9 kg from Monday to Wednesday.

How much rice did he use on Wednesday?

Step 1: 2.5kg + 1.75kg =___kg

Solution

Mr Li used 2.5kg of rice on Monday and 1.75 kg more on Tuesday. He used a total of 9 kg from Monday to Wednesday.

How much rice did he use on Wednesday?

2.50

+ 1.75

Step 1: 2.5kg + 1.75kg = 4.25kg

He used 4.25kg of rice on Tuesday.

Solution

Mr Li used 2.5kg of rice on Monday and 1.75 kg more on Tuesday. He used a total of 9 kg from Monday to Wednesday.

How much rice did he use on Wednesday?

2.50

+ 4.25

Step 2: 2.5kg + 4.25kg = 6.75kg

He used 6.75kg of rice on Monday and Tuesday.

Solution

Mr Li used 2.5kg of rice on Monday and 1.75 kg more on Tuesday. He used a total of 9 kg from Monday to Wednesday.

How much rice did he use on Wednesday?

9.00

- 6.75

Step 3: 9.00 kg - 6.75kg = 2.25 kg

He used 2.25kg of rice on Wednesday.

Multiplication in decimals

Try this out!

1. The length of ribbon A is 10.08 m.

Ribbon B is 3 times as long as ribbon A.

Find the length of ribbon B.

Try this out!

1. The length of ribbon A is 10.08 m.

Ribbon B is 3 times as long as ribbon A.

Find the length of ribbon B.

Let’s draw models to help us visualize the scenario.

Try this out!

1. The length of ribbon A is 10.08 m.

Ribbon B is 3 times as long as ribbon A.

Find the length of ribbon B.

A

10.08m

Try this out!

1. The length of ribbon A is 10.08 m.

Ribbon B is 3 times as long as ribbon A.

Find the length of ribbon B.

A

10.08m

B

Try this out!

1. The length of ribbon A is 10.08 m.

Ribbon B is 3 times as long as ribbon A.

Find the length of ribbon B.

A

10.08m

B

?

Try this out!

1. The length of ribbon A is 10.08 m.

Ribbon B is 3 times as long as ribbon A.

Find the length of ribbon B.

10.08 x 3 =_____m

A

10.08m

B

?

Do multiplication workings accordingly

10.08

x 3

Do multiplication workings accordingly

10.08

x 3

4

+2

Do multiplication workings accordingly

10.08

x 3

24

+2

Do multiplication workings accordingly

10.08

x 3

.24

Place the decimal place in a straight line.

Do multiplication workings accordingly

10.08

x 3

0.24

Do multiplication workings accordingly

10.08

x 3

30.24

Try this out!

1. The length of ribbon A is 10.08 m.

Ribbon B is 3 times as long as ribbon A.

Find the length of ribbon B.

10.08 x 3 =30.24m

A

10.08m

B

30.24m

Are you ready to try out the questions?

Visit kungfumath.sg today!