Parents Guide to Long Multiplication
Parents Guide to Long
Multiplication
This Power Point Presentation will
Show Parents the Language We Use
When Teaching Children Long
Multiplication
Introducing Long
Multiplication
We introduce long multiplication first of all by looking at multiplying by 20, 30, 40 etc.
Example
54 62
X20 x30
Always multiply by the units first:
54
X 20
We say, “54 multiplied by zero.”
Then we say, “54 multiplied by 2.”
5 4 x 20
Multiplying by 20
We introduce this calculation by saying:
54 multiplied by zero is zero.
When we multiply by zero the answer is always zero!
Put your zero in the answer.
Now we multiply 54 by 2.
We say 2 fours are 8. Put down your 8.
Now we say 2 fives are 10.
This is the end of the sum so put down the 10 in the answer.
10
4 6 x 20
Example 2
We introduce this calculation by saying:
46 multiplied by zero is zero.
When we multiply by zero the answer is always zero!
Put your zero in the answer.
Now we multiply 46 by 2.
We say 2 sixes are 12. Put down your 2 and carry your 1.
Now we say 2 fours are 8 add 1 is 9.
This is the end of the sum so put down the 9 in the answer.
9 1
Remember: when we multiply by zero, the answer is always zero!
Try These:
52
X 20
48
X 40
29
X 30
95
X 40
94
X 40
34
X 20
28
X 50
83
X 30
34
X60
Long Multiplication
Step 1 Step 2 Step 3
32
X 23
32
X 3
96
32
X 20
640
96
+640
Long multiplication is really 3 sums in one!
Step 1: multiply the top number by the units digit in the bottom number.
Step 2: Multiply the top number by the tens digit in the bottom number.
Step 3: add your two answers.
Be careful with your place value!
To remind us to keep the figures in the correct place, we talk about the magic 0!
46
X 2 3
138 Multiply 46 by 3
92 0 Put in your magic nought! Now do 46 multiplied by 2
1058 Finally add your two answers together!
Notice that without your magic nought the digits 9 and 2 would not be in the correct place & your answer would be incorrect.
76
X23
32
X 41
Now try these:
82
X46
46
X 54
93
X54
64
X 32
Remember: Long multiplication is really 3 sums in one!
Step 1: multiply the top number by the units digit in the bottom number.
Step 2: Multiply the top number by the tens digit in the bottom number.
Step 3: add your two answers.
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Our School Website.
We hope this powerpoint will help you to work with your child at home.
Please ask in school if you have any questions regarding our approach to teaching maths.
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