In the book "The Secret Life of Math",

(click

**here**for my earlier blog post about this book)a few ways of multiplying is introduced,

this is one we really like.

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Let's try something simply like 45 x 78

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Since both numbers are in tens,

so we need two boxes at each sides

which altogether makes four boxes.

Write 45 across at the top and 78 down on the right

or vice versa.

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In each box, draw a slanted line from top right to bottom left

and continue drawing it out of the box.

Do the same with all the boxes.

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Now is time to do the calculation.

4 x 7 = 28,

write the answer in the box with the TEN (2) on top and UNIT (7) below.

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Repeat this step with all the numbers.

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Plus the numbers follow the SLANTED boxes,

in this case, the number is 0

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5 + 4 + 2 = 11

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Leave the UNIT at its place,

move the TEN to the next line.

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3 + 8 + 3 + 1 = 15

leave the 5 at its place and move the 1 to the next line.

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2 + 1 = 3

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The answer is 3510

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