Year 4 Maths 8.1.21

LO: Use efficient methods to multiply.

Starter: True or false?

18 x 4 = 10 x 8 x 4

Success Criteria: -Use partitioning.

-Use the knowledge of doubling.

-Use repeated addition.

LO: Use efficient methods to multiply.

18 x 4 = 72 10 x 8 x 4= 320 It is false.

Success Criteria: -Use partitioning.

-Use the knowledge of doubling.

-Use repeated addition.

LO: Use efficient methods to multiply.

What is an efficient method?

Success Criteria: -Use partitioning.

-Use the knowledge of doubling.

-Use repeated addition.

LO: Use efficient methods to multiply.

What methods could you use to calculate 6 8 if you did not know the answer?

Success Criteria: -Use partitioning.

-Use the knowledge of doubling.

-Use repeated addition.

LO: Use efficient methods to multiply.

6 8

48

What methods could you use to calculate 6 8 if you did not know the answer?

Have a think

I partitioned 6 into 5 and 1 8 56

5 8 40

1

1 8 8

Success Criteria: -Use partitioning.

-Use the knowledge of doubling.

-Use repeated addition.

LO: Use efficient methods to multiply.

6 8

48

What methods could you use to calculate 6 8 if you did not know the answer?

2 3

6 8 2 3 8 Double 24 is 48

3 8 24

3 8 24

Success Criteria: -Use partitioning.

-Use the knowledge of doubling.

-Use repeated addition.

LO: Use efficient methods to multiply.

6 8

48

What methods could you use to calculate 6 8 if you did not know the answer?

6 8 6 2 4

6 2 4

6 2

12 4 48

6 2 4

24 2 48

Success Criteria: -Use partitioning.

-Use the knowledge of doubling.

-Use repeated addition.

LO: Use efficient methods to multiply.

6 8

48

What methods could you use to calculate 6 8 if you did not know the answer?

I did 6 10 then subtracted 12 10 6 10 60

6

60 12 48

Success Criteria: -Use partitioning.

-Use the knowledge of doubling.

-Use repeated addition.

Challenge 1 Questions

Challenge 2

Remember today’s lesson is all about finding the quickest way for you to answer the question.

Your chosen method might not be the same as somebody else’s!

1) 2) 3) 4) 5) 6) 7) 8)

19 x 7= 12 x 6= 38 x 10= 74 x 3= 13 x 6= 27 x 3= 14 x 6= 55 x 3=

LO: Use efficient methods to multiply.

Which method is your first choice when multiplying a 1-digit number to a 2-digit number?

Success Criteria: -Use partitioning..

-Use the knowledge of doubling.

-Use repeated addition.

Answers Challenge 1

Answers Challenge 2

1) 2) 3) 4) 5) 6) 7) 8)

133 72 380 222 78 81 84 165