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Lesson 5.1: Multiplication
This Lesson demonstrates multiplying 23 * 42

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Lesson 5.1: Multiplication (23*42)
First Represent 23 as 20...
(pending operation)
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Lesson 5.1: Multiplication (23*42)
...and 3.
(This is 23)
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Lesson 5.1: Multiplication (23*42)
We Represent 4 as 40, so...
(pending operation)
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Lesson 5.1: Multiplication (23*42)
...and 2.
(This is 42)
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Lesson 5.1: Multiplication (23*42)
2*3=6  so add as 5+1.
5....
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Lesson 5.1: Multiplication (23*42)
... 1 part
(For 6)
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Lesson 5.1: Multiplication (23*42)
2*2=4
So... add 40 (for 46)
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Lesson 5.1: Multiplication (23*42)
Shift decimal to the left.
(For 4.6)
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Lesson 5.1: Multiplication (23*42)
4*3=12
Add 2 part of 12 as 5-3, so +5 (for 9.6....)
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Lesson 5.1: Multiplication (23*42)
Add -30 part
(For 6.6)
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Lesson 5.1: Multiplication (23*42)
Add 10 of 12
(For 16.6)
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Lesson 5.1: Multiplication (23*42)
4*2=8
Add 80 as 50+30, so add 50 (for 66.6...)
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Lesson 5.1: Multiplication (23*42)
and add 30
(For 96.6)
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Lesson 5.1: Multiplication (23*42)
Restore decimal, shift to the right.
Result 966
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Conclusion: (End)
Using the auxiliary abaci to keep the multiplicands
and using the primary to add up from the results.
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