How many zero are there in quadrillion?

There are two correct answers to this question:

15 (in the USA and in any countries that use "short scale" naming conventions)

Or

24 (in countries that use "long scale" naming conventions)

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The scales goes as follows:

Value in

Scientific notation

| Short Scale Name |

| Value in numerals

Long Scale Name

10 01oneone

10 31,000thousandthousand

10 61,000,000millionmillion

10 91,000,000,000billionthousand million or milliard

10121,000,000,000,000trillionbillion

10151,000,000,000,000,000quadrillionthousand billion or billiard

10181,000,000,000,000,000,000quintilliontrillion

10211,000,000,000,000,000,000,000sextillionthousand trillion or trilliard

10241,000,000,000,000,000,000,000,000

septillionquadrillion

The two scales are fairly easy to work out:

• The long scale as used in countries like Europe:

The scale is based on powers of a million:

billion = bi-million = million2 = (106)2 = 1012 = 12 zeros.

Trillion = tri-million = million3 = (106)3 = 1018 = 18 zeros.

Quadrillion = quad-million = million4 = (106)4 = 1024 = 24 zeros

etc.

ie Take the naming idenitifier and raise a million to the power of that.

• The short scale as used in countries like USA:

The scale is based on powers of a thousand plus one:

billion = bi-million = (103)2+1 = 109 = 9 zeros

trillion = tri-million = (103)3+1 = 1012 = 12 zeros

quadrillion = quad-million = (103)4+1 = 1015 = 15 zeros

etc

ie Take the naming identifier, add one and raise a thousand to the power of that.

The naming identifiers are:

bi- (2), tri- (3), quad- (4), quin- (5), sex- (6), sept- (7), oct- (8), non- (9), dec- (10), etc (the prefix is based on latin numbers).