ISBN-10 Validity
Have you ever looked at the back of a book and above the barcode there is a number? Well, that is how books are classified internationally. Prior to 2007, ISBN-10 (International Standard Book Number) was standard. With it now being phased out, ISBN-13 has taken its spot! ISBN-10 is still common today, with books being published with both ISBN-10 and ISBN-13 on the back! Did you also know that the validity of ISBN-10 can be figured out by math? I would like to show you how! For this example, we will be using this ISBN-10.
ISBN-10: 1-932698-18-3
To figure out if an ISBN-10 number is valid you have to follow these steps!
First, write down the whole ISBN-10 number.
1-932698-18-3
Remove the dashes.
1932698183
Second, similar to UPCs, Bank Routing Numbers, and Money Orders, you have to multiply the ISBN-10 by the weight!
In ISBN-10, The weight is: 10,9,8,7,6,5,4,3,2,1.
(I will put it in a grid to make it easier to visualize)
1 | *10 | 10 |
9 | *9 | 81 |
3 | *8 | 24 |
2 | *7 | 14 |
6 | *6 | 36 |
9 | *5 | 45 |
8 | *4 | 32 |
1 | *3 | 3 |
8 | *2 | 16 |
3 | *1 | 3 |
Third, add all of the products together!
10+81+24+14+36+45+32+3+16+3 =
264
Finally, divide the number by 11, and if the number divides evenly by 11, (meaning there is no remainder) then it is valid!
264/11 =
24
(This isn’t the only way to check for validity with an ISBN-10 number, but it is a quick way to identify the validity of the book!)
Now that you know how to identify the validity of a book, you can now buy a book knowing how to identify it and how to make sure it is valid!