数 as used in math - pronounced かず or すう?


Eg in definition of 根：ある数を何乗かした数に対するもとの数。

Is it pronounced かず or すう?




In everyday conversations, it's always read as かず. But in mathematical
contexts, 数 on its own is usually read as **すう**. すう becomes dominant in math
classes after you graduate from elementary school and start saying things like
these.

>   * 負【ふ】の **数【すう】**  
>  negative number
>   * 複素数【ふくそすう】とは実数【じっすう】 _a_ , _b_ と虚数【きょすう】単位【たんい】 i を用いて、 _a_ + _bi_
> の形で表すことのできる **数【すう】** である。  
>  A complex number is a number that can be expressed in the form _a_ + _bi_ ,
> where _a_ and _b_ are real numbers and _i_ is the imaginary unit.
>

Reading these 数 as かず is not wrong at all, but it sounds less technical.




In everyday conversations, it's always read as かず. But in mathematical
contexts, 数 on its own is usually read as **すう**. すう becomes dominant in math
classes after you graduate from elementary school and start saying things like
these.

>   * 負【ふ】の **数【すう】**  
>  negative number
>   * 複素数【ふくそすう】とは実数【じっすう】 _a_ , _b_ と虚数【きょすう】単位【たんい】 i を用いて、 _a_ + _bi_
> の形で表すことのできる **数【すう】** である。  
>  A complex number is a number that can be expressed in the form _a_ + _bi_ ,
> where _a_ and _b_ are real numbers and _i_ is the imaginary unit.
>

Reading these 数 as かず is not wrong at all, but it sounds less technical.

