Arabic multiplication (XIVth century)



Each square shows the product of the number at the top of the column and the number on the right of the table, with the tens and units separated (written in apart in the two triangles).
For example : 3 X 5 = 1(ten)5(units)
You get the answer to the multiplication by adding up the squares and triangles diagonally -don't forget to carry any tens and hundreds etc...
For example, the answer in the tens column is 0 because 8 + 0 + 2 = 10,
so write '0' and carry '1'.
327 x 541 = 176 907