# How to pronounce 5x10^5, e.g.

#### Nona1991

##### Member
Hi everyone!!

I wanted to know how scientific notation numbers are pronunced in english. E.g. 5x105, 2x108, or whatever!

• #### entangledbank

##### Senior Member
Normally I'd say five by ten to the five and two by ten to the eight. The power can be expressed by longer forms - we say ten to the five, ten to the power of five, or ten to the fifth power - but in a more complex expression like this, I'd use the short form.

#### Nona1991

##### Member
Thanks a lot entangledbank!

#### Egmont

##### Senior Member
In American English, we'd say "five times ten to the fifth" or "five times ten to the fifth power" for the first one. Similarly, the second would be either "two times ten to the eighth" or "two times ten to the eighth power."

The two differences between that and the BE version that entangledbank gave earlier is (a) we say times, not by, and (b) we always use the ordinal form of the exponent, not the cardinal form.

#### e2efour

##### Senior Member
We also usually say times and ten to the fifth in the UK.
I would personally only use by when talking about the dimensions of an object, e.g. a piece of paper measuring ten by five centimetres.

#### natkretep

##### Moderato con anima (English Only)
In maths at school, we were taught to say 'ten to the power of five', and we had a teacher who said 'ten raised to five'.

#### e2efour

##### Senior Member
I suppose it largely depends on what you first hear at school. I don't know what children are taught nowadays, but I have never actually heard anyone say ten to the five instead of ten to the fifth.
But I didn't study mathematics at university!

#### Egmont

##### Senior Member
...But I didn't study mathematics at university!
I did, through graduate-level courses while studying for a Ph.D. in engineering - but I don't think that's meaningful here. My math instructors weren't chosen for their knowledge of English. Some of them weren't even native speakers. They knew more than I ever will about where exponents come from, but as a group they were not good role models for the right way to say them.

#### mathman

##### Senior Member
In American English, we'd say "five times ten to the fifth" or "five times ten to the fifth power" for the first one. Similarly, the second would be either "two times ten to the eighth" or "two times ten to the eighth power."

(snip)
I agree, though one also hears "five times ten to the five" (though because of the repetition of the "five," that would sound a little awkward, and "fifth" would be more usual). But "two times ten to the eight" is common (though less common than "to the eighth").

When the exponents are negative, one rarely (in my experience) uses the ordinal: 4 x 10^(- 3) is said as "four times ten to the minus three" or "four times ten to the negative three." I don't think I have heard anyone use "four times ten to the negative third" in a professional context, though it wouldn't be wrong to say that: it just sounds odd (to me).

#### Egmont

##### Senior Member
... When the exponents are negative, one rarely (in my experience) uses the ordinal: 4 x 10^(- 3) is said as "four times ten to the minus three" or "four times ten to the negative three." I don't think I have heard anyone use "four times ten to the negative third" in a professional context, though it wouldn't be wrong to say that: it just sounds odd (to me).
And I agree with that: cardinal numbers for negative exponents.

#### RM1(SS)

##### Senior Member
I would say "four times ten to the minus third."

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