Question

9,99,99,851 in the international system​

Answer 1

$\huge\mathcal{\fcolorbox{aqua}{azure}{\red{♡Answer}}}$

We begin from the right and insert a comma after. Every three digits that is we divide the number into its periods. Then read each period separately. So we write the given number in standard form

Answer 2

Answer:

99,999,851 . This is the right answer