fix: mathematical precision

[cptbtptpbcptdtptp]

The number in JS uses the IEEE754 standard: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Number

IEEE754 conversion rules: https://www.h-schmidt.net/FloatConverter/IEEE754.html

$2^{53}\rightarrow 10^{15.95}$

[GuoLei1990]

Encoding is: $2^{\left( 2-v0\right) }\times \left( 1+v1\right)$ Maybe is $2^{52}-1\rightarrow 10^{15.65}$ Math.floor(15.653559774527022)=15 ?

[GuoLei1990]

Should fix Math unit test