Ethiopian multiplication is a method of multiplying integers using only addition, doubling, and halving.
<b>Method:</b>
<ol>
<li>Take two numbers to be multiplied and write them down at the top of two columns.</li>
<li>In the left-hand column repeatedly halve the last number, discarding any remainders, and write the result below the last in the same column, until you write a value of 1.</li>
<li>In the right-hand column repeatedly double the last number and write the result below. stop when you add a result in the same row as where the left hand column shows 1.</li>
<li>Examine the table produced and discard any row where the value in the left column is even.</li>
<li>Sum the values in the right-hand column that remain to produce the result of multiplying the original two numbers together</li>
</ol>
<b>For example:</b> 17 × 34
<pre>
17 34
</pre>
Halving the first column:
<pre>
17 34
8
4
2
1
</pre>
Doubling the second column:
<pre>
17 34
8 68
4 136
2 272
1 544
</pre>
Strike-out rows whose first cell is even:
<pre>
17 34
8 <strike>68</strike>
4 <strike>136</strike>
2 <strike>272</strike>
1 544
</pre>
Sum the remaining numbers in the right-hand column:
<pre>
17 34
8 --
4 ---
2 ---
1 544
====
578
</pre>
So 17 multiplied by 34, by the Ethiopian method is 578.