Year 4 Maths 12.1.21

LO: Use the compact multiplication method to multiply.

Starter

Success Criteria:

-Place the largest number on top of the smaller number.

-Partition the larger number and multiply each part by the smaller number, starting with the ones column.

-Add both of the numbers made together.

What do we need to remember when using this method?

-Always start with the ones column when multiplying -The largest number should always be above the other number -Always remember to add the numbers at the end

Compact method (Also known as short multiplication)

76 x 3 =

76 x _____ 3

Compact method

76 x 3 = 76 x _____ 3 8 _____ 1

Compact method

76 x 3 = 76 x _____ 3 228 _____ 1

Compact method Expanded method

97 x 2 =

97 x _____ 2 194 _____ 1

97 x 2 =

97 x____ 2 2x7= 14 + 2x90= ____ 180 1 94 ____

Here is a video that explains the method really well- one last example before you have a try. https://www.youtube.com/watch?v=cBe3RYJRODk

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Questions Set 1 2.

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Questions Set 2 No exchanging

Challenge: Explain the mistakes you see in this calculation. Can you try the question for yourself and correct it?

99 x 8=

Answers Starter: They have mistaken the 4 for 4 ones instead of its true value of 40.

Set 1 1. a. 228 b. 213 c. 405 d. 260 e. 232 f. 68 2. £280 3. 136 4. 259 5. 168 Challenge: The largest number is not at the top. They have tried to subtract the tens and ones at the end instead of add. 99 x 8= 792

Set 2