Basic of NCERT

When $\frac{7}{2^{4}}$ it's decimal terminate after 4 place of decimal. This pattern of termination happens with every case if denominator is the only of 2, 5. Example $\frac{7}{2^{4}5^{3}}$ in this case also it will terminate after 4 decimal place because power of 2 is greater than 5.

Similarly $\frac{2579150574}{(21)(6)(2)^{10}}$ Here, 21 and 6 get cancle by nominator and only 2^10 would be left as denominator. So it will terminate after 10 of decimal place.