Formula use: \left(a-b\right)^3=a^3-3.a^2.b+3.a.b^2-b^3

Explanation

Here, given expression is :
6.55\times6.55\times6.55\ – 3×6.55×6.55×1.55 + 3×6.55×1.55×1.55 – 1.55×1.55×1.55
Let,
6.55 = a
1.55 = b
Now, find the value :
6.55\times6.55\times6.55-3\times6.55\times6.55\times1.55\ +\ 3\times6.55\times1.55\times1.55\ -1.55\times1.55\times1.55
\rightarrow\left(6.55\right)^3-3.\left(6.55\right)^2.1.55+3\times6.55\times\left(1.55\right)^2-\left(1.55\right)^3
\rightarrow a^3-3.a^2.b+3.a.b^2-b^3
\rightarrow\left(a-b\right)^3
\rightarrow\left(6.55-1.55\right)^3
\rightarrow\left(5\right)^3
\therefore 125
Ans: 125.